Classic French Opera Cake

Instructions

1. Preheat oven to 425 F with racks in the upper and lower thirds. Line two 15x12-inch rimmed pans with buttered parchment paper.

2. Beat egg whites until foamy, then gradually add sugar, beating until glossy and stiff peaks form.

3. In a separate bowl, beat ground almonds, confectioners' sugar, and whole eggs until light and foamy.

4. Stir flour into the almond batter.

5. Fold 1/4 of the almond batter into egg whites, then fold in the remaining almond batter and cooled melted butter.

6. Divide batter into prepared pans and bake 5-7 minutes until cakes spring back when touched.

7. Cool cakes, then invert onto a clean surface, peel off parchment, and cover loosely to prevent drying.

8. Dissolve espresso powder in boiling water; set aside.

9. Bring sugar, water, and vanilla to a boil in a saucepan, cook to 255 F, then remove from heat and cool slightly.

10. Beat egg and egg yolk until fluffy.

11. Slowly pour warm sugar syrup into eggs while beating.

12. Beat in the dissolved coffee mixture.

13. Gradually add butter one tablespoon at a time, beating until thick and fluffy.

14. Bring milk and cream to a boil in a saucepan.

15. Remove from heat, then stir in chocolate until melted and smooth.

16. Stir in butter until fully combined.

17. Line a baking sheet with parchment. Cut two 10x10-inch squares from the cake layers; place one on the sheet.

18. Trim remaining 12x5-inch cake rectangles to 10x5-inch.

19. Spread 3/4 of the coffee buttercream over the first cake square.

20. Arrange the two 10x5-inch cake rectangles side by side on top of the buttercream to form a square.

21. Spread ganache evenly over the cake rectangles.

22. Top with the second 10x10-inch cake, spread with remaining buttercream, then chill for 1 hour.

23. Melt butter in a saucepan, skim solids to clarify.

24. Melt chocolate, then whisk in clarified butter until smooth. Pour glaze evenly over the cake.

25. Chill for 1 hour to set, then trim edges before serving.