1 box (15.25 oz) Betty Crocker™ Super Moist™ Cake Mix Butter Recipe Yellow
1 small box (3.4 oz) vanilla pudding mix
1/3 cup butter, softened and cut into small pieces
1/2 cup sour cream
3/4 cup milk
3 large eggs
Pastry Cream:
1 1/4 cup heavy whipping cream
1/3 cup sugar
3 tablespoons flour
1/8 teaspoon salt
3 egg yolks
3/4 teaspoon vanilla paste or pure vanilla extract
Chocolate Glaze:
1/4 cup heavy whipping cream
1 tablespoon corn syrup
4 ounces semi-sweet chocolate, finely chopped
CAKE: Line a long loaf pan (13 x 5 x 3-inch) with tin foil. Spray any uncovered area with non-stick spray. Preheat oven to 350º F. Combine cake mix, pudding mix, butter, sour cream, milk and eggs. Beat on low speed using an electric mixer for 30 seconds. Increase mixer speed to medium and beat for 2 minutes. Pour batter into loaf pan. Bake for 48-52 minutes until a toothpick inserted in the center comes out clean. Cool cake in pan for 10 minutes, then remove and set on cooling rack to cool completely. PASTRY CREAM: While cake is baking, make the pastry cream. Heat heavy whipping cream in a saucepan set over medium heat just until steam rises from the pan. Remove from heat. Whisk together the flour, sugar, salt and egg yolks. Continue to whisk as you slowly drizzle the hot cream into the mixture. Return mixture to the saucepan, set over medium low heat and whisk constantly until thickened for 2-4 minutes. Pour through a fine mesh strainer set over a bowl. Press a piece of plastic wrap directly on top of the pastry cream and refrigerate until well chilled. CHOCOLATE GLAZE: Pour heavy whipping cream, corn syrup and chocolate into a microwave safe bowl. Heat in microwave on high for 30 seconds. Let sit in microwave for 3 minutes. Remove and stir until smooth. If not all melted, heat for 10 second increments, stirring after each until melted. Allow to cool and thicken slightly. ASSEMBLE CAKE: Cut a 1-inch slice horizontally from the cake to make the top and bottom more closely resemble the two pieces of an éclair. Save the slice for another use. Spread pastry cream between the two cake layers. Pour chocolate glaze over top of the cake.