Boston Cream Pie
When America's Test Kitchen sends you a copy of their new cookbook and asks you to review and publish a recipe on your blog, you do it. You also do it while skipping around your house because it's America's Test Kitchen and their knowledgeable test cooks, editors, and cookware specialists put the time and effort into perfecting recipes, a practice I value and respect.
I've had the pleasure of working with America's Test Kitchen for the past 2 years when I reviewed Naturally Sweet cookbook and published chewy chocolate chip cookies with less sugar, then again with The Perfect Cookie and black and white cookies. My bookshelves are full of cookbooks, but I say with 100% honesty that my most used books are those authored by ATK.
Flipping through their latest cookbook, The Perfect Cake, influences me to immediately get up, run to the kitchen, and begin hoarding... I mean softening... sticks of butter. The cookbook is home to more than 240 kitchen tested cake and cupcakes recipes that promise recipe success ranging from classics like yellow sheet cake and tres leches cake to modern like rainbow cake and bananas foster cake. If it wasn't Boston cream pie stealing my heart, it was the masterfully gorgeous blackberry mascarpone lemon cake. ♥ If you enjoy baking cakes, you need this cookbook.
I chose Boston cream pie because if anyone's going to do this classic recipe justice-- completely from-scratch and unapologetically decadent-- it's ATK. You don't mess with Boston cream pie.
BEHIND THE RECIPE
Boston cream pie, I learned, was a cake dreamed up back in the 1800s and is called pie because the most common bakeware item over 160+ years ago was a pie plate. Boston cream pie is very much a cake and very much an intimidating recipe if you aren't prepared with some helpful tips, careful directions, step-by-step photos, and a video tutorial to help guide you. Turns out Boston cream pie is not terribly difficult if you break the recipe down into 3 parts:
- pastry cream
- sponge cake
- chocolate glaze
I have everything laid out for you and I REALLY hope you try this one!
The recipe begins with homemade pastry cream. You can watch me prepare the pastry cream in the recipe video below, a helpful crutch if you've never tempered eggs before. The pastry cream is every ounce of rich you imagine, made from life's best ingredients like butter, egg yolks, vanilla extract, and sugar. The egg yolks must be gently cooked so you'll temper them with the warm half-and-half you're cooking on the stove. Remember to whisk the pastry cream constantly as it cooks and thickens.
Buttery, sweet, smooth, and creamy, the vanilla pastry cream must cool completely before spreading on the cake. To save time the day you're serving the cake, prepare the pastry cream in advance.
Pastry cream will be thick right off the stove.
For a smooth cream, strain to rid any lumps.
Place plastic wrap on surface when cooling.
The sponge cake itself is light and springy, a pleasing contrast to the thick pastry cream and chocolate glaze on top! Sponge cakes are named for their delicate and airy texture, a result from (1) a high egg to flour ratio and (2) the air beaten into the eggs. America's Test Kitchen teaches us the "hot milk sponge cake" method which skips separating eggs and meticulous folding. Instead, you'll whisk a warm butter + milk mixture into whipped eggs + sugar, then whisk in the cake's dry ingredients. The warm milk keeps the butter melted so that it mixes seamlessly into the batter. Just 3 bowls of ingredients all whisked together-- a great recipe for sponge cake beginners. I appreciate this simplified method since there are many other steps in the Boston cream pie recipe!
The sponge cake's ingredients are pretty similar to the pastry cream's ingredients. This is what I LOVE MOST about baking. It's the same ingredients just beaten, mixed, and cooked in different ways. Magic.
The final sponge cake batter will be airy, a preview of the final product. I loved this fluffy sponge cake so much and I'm already dreaming of different ways to serve it. Whipped cream, fresh berries, lemon curd, jam, soaked with liquors, maybe a tiramisu cake of sorts? It's an incredible building block recipe for summer desserts and I'm looking forward to playing around with it!!
DON'T MAKE MY MISTAKE!
Even though the sponge cake is quite easy, I ran into a major cake catastrophe. This isn't a fault of America's Test Kitchen's recipe, but my own oversight in the directions. By skipping over a few words in the recipe, I managed to ruin my sponge cakes... twice. That's four 9-inch cakes completely ruined. Don't make my mistake and read the recipe: line the cake pans with parchment paper. While you're at it, grease the pans before and after lining with parchment paper too. This is your safety net to guarantee the cake won't stick to the pan.
Because even if you grease the pans and skip the parchment paper, the cakes WILL stick. It's heartbreaking.
I'll go into more details about my little blunder this weekend when I share another Latest Recipe Testing blog post!
Rounding out our Boston cream pie is a veil of chocolate glaze. Made from 3 ingredients, this chocolate glaze is thick, smooth, and if you let it sit for a few minutes before stirring, is thick enough to cling on the sides of the cake. You'll heat heavy cream and a bit of corn syrup together on the stove before pouring over finely chopped chocolate. The corn syrup provides shine and sticking power to the ganache-like glaze and I highly recommend its addition. Honey should make a nice substitution, though I haven't tried it myself.
Poured and spread on top, the glaze is the grand finale, the finishing touch, the pièce de résistance on a supremely satisfying and show-stopping dessert!
Ladies and gents, may I present you with the recipe and my video for America's Test Kitchen's Boston cream pie!
Boston Cream Pie
- 2 cups (480ml) half-and-half
- 6 large egg yolks, at room temperature
- 1/2 cup (100g) granulated sugar
- 1/8 teaspoon salt
- 1/4 cup (31g) all-purpose flour (spoon & leveled)
- 1/4 cup (4 Tablespoons; 60g) unsalted butter, cut into 4 pieces
- 1 and 1/2 teaspoons pure vanilla extract
- 1 and 1/2 cups (190g) all-purpose flour (spoon & leveled)
- 1 and 1/2 teaspoons baking powder
- 3/4 teaspoon salt
- 3/4 cup (180ml) whole milk
- 6 Tablespoons (85g) unsalted butter
- 1 and 1/2 teaspoons pure vanilla extract
- 3 large eggs, at room temperature
- 1 and 1/2 cups (300g) granulated sugar
- 1/2 cup (120ml) heavy cream
- 2 Tablespoons light corn syrup
- 4 ounces (113g) bittersweet chocolate, finely chopped
- Read the recipe and watch the helpful video above before beginning as there are many little steps that are time sensitive or require cooling.
- Make the pastry cream: Heat half-and-half in a medium saucepan over medium heat until simmering. Meanwhile, whisk egg yolks, granulated sugar, and salt together in a bowl until smooth. Add flour and whisk until combined. Mixture will be thick. Whisk about 1/2 cup half-and-half into yolk mixture to temper, then slowly whisk tempered yolk mixture into half-and-half in the saucepan. Reduce heat to medium-low and continue to cook, whisking constantly, for 5 minutes as the mixture thickens. (America's Test Kitchen instructs for 7-8 minutes, but mine began thickening quickly.)
- Increase heat to medium and cook, whisking vigorously, until bubbles burst on the surface, about 1 minute. Remove from heat and whisk in the butter and vanilla extract until combined. Pastry cream will be thick. Strain through a fine-mesh strainer set over a bowl. Press plastic wrap directly on surface of pastry cream and refrigerate until set, at least 2 hours and up to 24 hours.
- Preheat the oven to 325°F (163°C). Grease two round 9-inch cake pans, line with parchment paper, then grease the parchment paper. You must use parchment!!! See recipe note.
- Make the cake: Whisk flour, baking powder, and salt together in a small bowl. In the microwave or on the stove, heat milk and butter together until butter has melted. Stir in the vanilla extract. Cover loosely to keep warm. In a large bowl using a hand mixer or a stand mixer fitted with a whisk attachment, whip the eggs and granulated sugar together on high speed until light and creamy, about 4 minutes. Add hot milk mixture and whisk by hand until combined, then whisk in the dry ingredients. Batter will bubbly on top and somewhat thick, similar to pancake batter.
- Divide batter evenly between 2 pans. Bake until the tops of cakes are light brown and a toothpick inserted in the center comes out clean, about 20-22 minutes.
- Remove cakes from the oven and set on a wire rack. Allow to cool completely in the pan. As the cakes cool, check the pastry cream in the refrigerator. If it's too thick, it won't easily spread and could tear the cake. I remove pastry cream from the refrigerator about 20 minutes before assembling the cake.
- Assemble the cake: Once cakes are cool, run a thin knife around the edges to release them from the pans. Place bottom cake layer on your cake stand or serving plate. Spread pastry cream evenly on top. Place second cake layer on top and gently press down to adhere to the pastry cream. Refrigerate cake while preparing the chocolate glaze.
- Make the glaze: Heat heavy cream and corn syrup in a small saucepan over medium heat until just simmering. As it heats up, place chocolate in a heat-proof glass bowl with a pouring spout (I use this 2-cup liquid measuring cup). Once simmering, remove cream from heat and pour over chocolate. Let sit, covered, for 5 minutes. Gently whisk until smooth.
- Pour glaze into the center of cake. Spread glaze to the edges of cake allowing it to gently drip down the sides. Refrigerate cake, uncovered, for at least 2 hours (and up to 24 hours) before slicing and serving. If chilling for longer than 2 hours, allow cake to come to room temperature before slicing and serving.
- Cover leftover cake tightly and store in the refrigerator for 5 days.
Make ahead tip: You can prepare pastry cream up to 24 hours in advance. See step 3. Baked and cooled cakes can also be prepared 24 hours in advance. Cover and store at room temperature, then continue with step 8. In order to maintain the proper consistency of the chocolate glaze, I recommend preparing right before pouring over cake. However, the entire assembled cake with chocolate glaze on top can be stored for up to 24 hours. See step 10. Pastry cream can weep and break if frozen, so I do not suggest freezing this cake. You can, however, freeze the baked and cooled cake layers for up to 3 months. Thaw overnight before using.
- Each ingredient is crucial to the finished cake. I do not recommend substitutions, though you can get away with using the same amount of whole milk instead of half-and-half in the pastry cream. This may be more convenient since whole milk is used for the sponge cake.
- Lots of leftover egg whites! Make a scramble or use some in any of these recipes.
- Feel free to leave out the corn syrup, though it's what adds shine and sticking power to the glaze. You can try substituting with honey.
- Any dark, bittersweet, or semi-sweet chocolate is a wonderful choice for the chocolate glaze. The corn syrup adds sweetness, so avoid anything very sweet.
- Parchment paper is a MUST for lining the cake pans. I failed this recipe 2x before discovering how crucial the parchment paper is. All cakes were ruined until I lined the cake pans with parchment paper on the 3rd try. Parchment paper guarantees the cakes will easily release from the pans. I simply traced and cut two 9-inch circles of parchment paper to line the bottom of the cake pans. Spray with nonstick spray or grease with butter before and after lining with parchment paper rounds.
Recipe reprinted in partnership with America's Test Kitchen from The Perfect Cake
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