Ingredients
Vanilla Sheet Cake
- 300 g Granulated sugar
- 113 g Unsalted butter (at room temperature)
- 110 g Oil
- 3 Eggs (at room temperature)
- 240 g Greek Yogurt (at room temperature)
- 1 teaspoon Vanilla extract
- 375 g All-purpose flour
- ½ teaspoon Salt
- 1 teaspoon Baking powder
- 1 teaspoon Baking soda
Pastry Cream
- 960 g Whole milk (3% fat)
- 200 g Granulated sugar
- 160 g Egg yolk (approximate yolk of 8 eggs)
- 50 g Corn starch
- 50 g All-purpose flour
- ½ tablespoon Vanilla extract
- 110 g Unsalted butter (82% fat, at room temperature)
Diplomat Cream Frosting
- 115 g Heavy cream (36% fat content, cold)
Chocolate Ganache Glaze
- 230 g Semi-sweet chocolate
- 230 g Heavy cream (36% fat content)
- 1 tablespoon Vegetable oil
Instructions
- Prepare the Vanilla Sheet Cake: Preheat your oven to 175℃ (350℉) and grease or line a 9×13-inch pan with parchment paper. In a large bowl, cream the butter and sugar until light and fluffy. Add oil, then eggs one at a time, mixing well after each. Mix in the yogurt and vanilla extract. Sift flour, baking powder, baking soda, and salt into the mixture, folding gently until just combined. Pour into the pan and bake for about 35 minutes until a toothpick comes out clean.
- Make the Pastry Cream: Halfway through baking, whisk sugar and egg yolks until fluffy. Add cornstarch, flour, and vanilla, mixing smooth. Heat milk to simmer, then temper the yolks by slowly whisking in hot milk. Return to heat, stir until thickened, then remove from heat and strain if needed. Blend in softened butter until smooth. Divide in half: one for filling the cake, the other for the frosting.
- Poke the Cake: When the cake is done and slightly cooled, use a wooden spoon handle to poke holes all over the surface. Pour half the warm pastry cream over the cake, filling the holes. Let the cake come to room temperature.
- Prepare Diplomat Cream Frosting: Whip the cold heavy cream until fluffy but not overwhipped. Loosen the reserved pastry cream with a few whisks, then gently fold in the whipped cream to keep it light and airy. Spread this frosting evenly over the cooled cake and refrigerate.
- Make Chocolate Ganache Glaze: Melt the chocolate partially in the microwave. Heat cream until just simmering and pour over the chocolate, stirring until smooth. Stir in vegetable oil. Let the glaze cool to about 30°C (86°F) until it has a smooth but spreadable consistency. Pour over the frosted cake and smooth with a spatula.
- Chill and Serve: Refrigerate the assembled cake for at least 4 hours before serving to allow flavors to meld and the glaze to set. Store any leftovers covered in the refrigerator for 1-2 days.
Notes
- Use room temperature ingredients for better mixing and cake texture.
- Do not overmix the batter to ensure a tender crumb.
- Temper the egg yolks carefully to prevent curdling in the pastry cream.
- Be careful not to overbake the cake to maintain moisture.
- Chill the cake sufficiently before serving for the best flavor and texture.
- The poke cake method allows the filling to soak into the cake, creating a moist and flavorful dessert.
- Prep Time: 30 minutes
- Cook Time: 35 minutes
- Category: Dessert
- Method: Baking
- Cuisine: American
