1 1/2 cups heavy cream
3 large egg yolks
1/3 cup sugar
4 teaspoons cornstarch
2 tablespoons butter, cut into 2 pieces
1 1/2 teaspoons vanilla extract
Cupcakes
1 3/4 cups flour
1 cup sugar
1 1/2 teaspoons baking powder
1/2 teaspoon salt
12 tablespoons unsalted butter, cut into 12 pieces and softened
3 large eggs, room temperature
3/4 cup whole milk, room temperature
1 1/2 teaspoons vanilla extract
Glaze
8 ounces bittersweet or semisweet chocolate, chopped
2/3 cup heavy cream
1/4 cup light corn syrup
1/2 teaspoon vanilla
Pastry cream
Bring the cream to a simmer in a medium saucepan over medium heat. Meanwhile, whisk the egg yolks, sugar, and salt together in a medium bowl, then whisk in the cornstarch until pale yellow and thick, about 30 seconds.
Slowly whisk the hot cream into the egg mixture to temper, then return the mixture to the saucepan and cook over medium heat, whisking constantly, until thick and glossy, about 1 1/2 minutes. Off the heat, whisk in the butter and vanilla. Transfer the mixture to a small bowl, press plastic wrap directly on the surface, and refrigerate until chilled and set, about 2 hours.
Cupcakes
Adjust an oven rack to the middle position and heat the oven to 350 degrees. Grease and flour a 12-cup muffin tin.
Whisk the flour, sugar, baking powder, and salt together in a large bowl. Using an electric mixer on medium-low speed, beat the butter into the flour mixture, one piece at a time, about 30 seconds. Continue to beat the mixture until it resembles moist crumbs, 1 to 3 minutes. Beat in the eggs, one at a time, until combined, about 30 seconds. Beat in the milk and vanilla, then increase the mixer speed to medium and beat the batter until smooth, light, and fluffy, 1 to 3 minutes.
Using a greased 1/3 cup measure, portion the batter into each muffin cup (about three-quarters full; do not overfill). 18-20 minutes.
Glaze
Microwave all ingredients together whisking often, until melted. 1-2 minutes. Let cool till it is thick but still pourable. About 20 minutes.
Cut into the cupcakes at an angle at the top (cut pretty deep). When you do this it should look like a pyramid. After you take of the top cut the cone off leaving 1/4 inch of the top. Fill the muffin with cream and place top back on. Pour the glaze over the cupcakes, letting it run down the sides. Refrigerate cupcakes until glaze has set, about 10 minutes.