Wicked Good Boston Cream Pie

1. FOR THE PASTRY CREAM: Heat half-and-half in medium saucepan over medium heat until just simmering. Meanwhile, whisk egg yolks, sugar, and salt in medium bowl until smooth. Add flour to yolk mixture and whisk until incorporated. Remove half-and-half from heat and, whisking constantly, slowly add 1⁄2 cup to yolk mixture to temper. Whisking constantly, return tempered yolk mixture to half-and-half in saucepan.
2. Return saucepan to medium heat and cook, whisking constantly, until mixture thickens slightly, about 1 minute. Reduce heat to medium-low and continue to simmer, whisking constantly, 8 minutes.
3. Increase heat to medium and cook, whisking vigorously, until bubbles burst on surface, 1 to 2 minutes. Remove saucepan from heat; whisk in butter and vanilla until butter is melted and incorporated. Strain pastry cream through fine-mesh strainer set over medium bowl. Press lightly greased parchment paper directly on surface and refrigerate until set, at least 2 hours or up to 24 hours.
4. FOR THE CAKE: Adjust oven rack to middle position and heat oven to 325 degrees. Grease two 9-inch round cake pans, line with parchment paper, grease parchment, and flour pans. Whisk flour, baking powder, and salt together in medium bowl. Heat milk and butter in small saucepan over low heat until butter is melted. Remove from heat, add vanilla, and cover to keep warm.
5. Using stand mixer fitted with whisk, whip eggs and sugar on high speed until light and airy, about 5 minutes. Remove mixer bowl from stand, add hot milk mixture, and whisk by hand until incorporated. Add dry ingredients and whisk until incorporated.
6. Working quickly, divide batter evenly between prepared pans and smooth tops with rubber spatula. Bake cakes until tops are light brown and toothpick inserted in centers comes out clean, 20 to 22 minutes.
7. Transfer cakes to wire rack and let cool completely in pan, about 2 hours. Run small knife around edge of pans, then invert cakes onto wire rack. Carefully remove parchment, then turn cakes right side up. (Cooled cakes can be wrapped tightly in plastic wrap and kept at room temperature for up to 1 day. Wrapped tightly in plastic, then aluminum foil, cakes can be frozen for up to 1 month. Defrost cakes at room temperature before unwrapping and frosting.)
8. TO ASSEMBLE THE CAKE: Line edges of cake platter with 4 strips of parchment paper to keep platter clean. Place 1 cake layer on prepared platter. Whisk pastry cream briefly, then spoon onto center of cake. Using rubber spatula, spread evenly to cake edge. Place second layer on top of pastry cream, bottom side up, making sure layers line up. Press lightly on top of cake to level. Refrigerate cake while preparing glaze.
9. FOR THE GLAZE: Bring cream and corn syrup to simmer in small saucepan over medium heat. Remove from heat, add chocolate, and let sit, covered, for 5 minutes. Whisk mixture gently until smooth.
10. Pour glaze onto center of cake. Use rubber spatula to spread glaze to edge of cake, letting excess drip decoratively down sides. Chill for at least 3 hours. Carefully pull out pieces of parchment from beneath cake before serving. (Assembled cake can be refrigerated for up to 1 day. Bring to room temperature before serving.)

Chill the assembled cake for at least 3 hours to make it easy to cut and serve.