Yield: about 30 cupcakes
For the pastry cream:
4 large egg yolks
½ cup sugar
¼ cup cornstarch
Pinch of salt
2 cups milk
1¼ tsp. vanilla extract
For the cupcakes:
9 tbsp. unsalted butter, at room temperature, plus more for greasing pans
2¼ cups all-purpose flour, plus more for pans
2¼ tsp. baking powder
¾ tsp. salt
¾ cup milk
4 large eggs plus 1 egg yolk
1½ cups sugar
1½ tsp. vanilla extract
For the ganache:
9 oz. semisweet or bittersweet chocolate, finely chopped
1 cup heavy cream
1½ tbsp. light corn syrup
- To make the pastry cream, place the egg yolks in a medium bowl and whisk. In a medium saucepan over medium heat, combine the sugar, cornstarch, and salt. Gradually add the milk in a steady stream and cook until the mixture thickens and starts to bubble, about 5 minutes. Whisking constantly, slowly add about a third of the hot milk mixture into the bowl with the egg yolks to temper. Return the contents of the bowl back into the saucepan with the remaining milk mixture. Continue to cook, whisking constantly, until the mixture comes to a full boil and is thick enough to hold its shape when lifted with a spoon, 2-4 minutes. Remove from the heat and stir in the vanilla. Strain the mixture through a fine mesh sieve into a heatproof bowl. Cover with plastic wrap pressed directly onto the surface of the cream to prevent a skin from forming. Refrigerate until chilled and firm, at least 2 hours and up to 2 days.
- To make the cupcakes, preheat the oven to 350˚ F. Lightly brush standard size muffin pans with melted butter. Coat the muffin wells with flour and shake out the excess. In a medium bowl, combine the flour, baking powder, and salt. Combine the milk and butter in a small saucepan over medium-low heat.
- Add the eggs, egg yolk, and sugar to the bowl of an electric mixer and beat on high speed until pale yellow, fluffy, and thick enough to ribbon when the spatula is lifted, about 5 minutes. Add the dry ingredients and mix on medium-low speed just until incorporated.
- Bring the milk mixture just to a boil. With the mixer on low speed, add the hot milk mixture in a slow, steady stream, mixing just until smooth. Blend in the vanilla.
- Fill the prepared muffin cups halfway with the batter. Bake, rotating the pans halfway through baking, until golden and a toothpick inserted in the center comes out clean, about 15 minutes total. Transfer the pans to a cooling rack and let stand for 10 minutes. Run a small offset spatula or knife around the edges of each cake to loosen. Turn the cakes out onto the cooling rack and let cool completely.
- To make the chocolate glaze, place the chocolate in a medium heatproof bowl. Combine the cream and corn syrup and bring to a simmer in a saucepan (or with short intervals in the microwave). Pour the hot cream over the chocolate and let stand 1-2 minutes until the chocolate begins to melt. Gently whisk the mixture until the chocolate is totally melted and a smooth ganache forms.
- To assemble the cupcakes, split each cake horizontally with a serrated knife. Spread about 1 tablespoon of the pastry cream on the bottom half of each cupcake. Replace the top halves. Spoon about 1 tablespoon of the chocolate glaze over each cupcake. Refrigerate at least 30 minutes before serving. (These can be made and assembled up to 1 day in advance.)