Raspberry Mousse Cake

Directions

1. 1
   Set a rack in the lower third of the oven and preheat to 350 degrees.
2. 2
   For the cake batter, whisk the egg yolks in a medium mixing bowl, just to break them up.
3. 3
   Whisk in half the sugar in a stream, then whisk in the vanilla and lemon zest.
4. 4
   Continue whisking for about a minute, or until the yolk mixture is pale and aerated.
5. 5
   Combine the egg whites and salt in the bowl of an electric mixer.
6. 6
   Whip the egg whites with the whisk attachment on medium speed until they are white, opaque, and just beginning to hold their shape.
7. 7
   Increase the speed to medium-high and whip in the remaining 1/3 cup sugar in a slow stream, continuing to whip the egg whites until they hold a firm peak.
8. 8
   Use a large rubber spatula to fold the yolk mixture into the egg whites.
9. 9
   Sift one-third of the flour mixture over the egg mixture, then fold in until combined.
10. 10
    Repeat with each remaining third of the flour mixture.
11. 11
    Scrape the cake batter into the pan and smooth the top.
12. 12
    Bake the cake for about 30 minutes, or until the cake is well risen and firm, and a toothpick inserted in the center emerges clean.
13. 13
    Immediately invert the cake to a rack to cool (if you leave a sponge cake of this type in the pan after its baked, it will shrink and fall).
14. 14
    Turn the cake right side up so that the paper is underneath.
15. 15
    Cool completely on a rack.
16. 16
    While the cake is baking, make the mousse.
17. 17
    Puree the raspberries in a food processor.
18. 18
    Strain out the seeds over a medium saucepan, letting the raspberry juice collect in the saucepan.
19. 19
    Bring the juice to a boil over medium heat, then lower the heat to maintain a steady, gentle simmer.
20. 20
    Cook the raspberry juice until it is reduced to 1 1/2 cups.
21. 21
    When the cake has cooled, trim the top away and use a long, sharp serrated knife to cut it in half horizontally.
22. 22
    Use a plate or other round pattern to trim the layers to an even 8-inch diameter so that their sides wont be visible in the finished cake.
23. 23
    Place one of the layers in a 9-inch springform pan.
24. 24
    To finish the mousse, put the water into a small heatproof bowl and sprinkle the gelatin on the surface.
25. 25
    Allow to soak for 5 minutes, then place the bowl over a small pan of simmering water and allow the gelatin to melt.
26. 26
    Combine the cooled raspberry puree, the gelatin, and the ricotta in a food processor or blender and pulse to mix smoothly.
27. 27
    Pour the mixture into a large mixing bowl.
28. 28
    For the meringue, half fill a medium saucepan with water and bring it to a boil over medium heat.
29. 29
    Combine the egg whites and sugar in the heatproof bowl of an electric mixer and whisk by hand a couple of times to mix.
30. 30
    Place the bowl over the pan of boiling water and whisk gently until the egg whites are hot and the sugar is dissolved.
31. 31
    Place on the mixer with the whisk attachment and whip on medium-high speed until the egg whites are cooled completely.
32. 32
    When you touch the outside of the bowl it wont be at all warm.
33. 33
    Fold the meringue into the raspberry mixture.
34. 34
    Pour half the mousse over the cake layer in the pan.
35. 35
    Place the second cake layer on the mousse and pour in the remaining mousse.
36. 36
    Smooth the top of the mousse with a metal offset spatula.
37. 37
    Chill the dessert to set the mousse, then cover the pan with plastic wrap.
38. 38
    You may leave it in the refrigerator for up to a couple of days before serving.
39. 39
    To unmold the dessert, insert a sharp paring knife between the mousse and the inside of the pan.
40. 40
    Scraping against the pan, not the mousse, run the blade all around the dessert.
41. 41
    Undo the clip of the springform side and lift it off.
42. 42
    Insert the knife an inch under the dessert to detach it all around from the base.
43. 43
    Use a wide spatula to slide the dessert off the springform base onto a platter.
44. 44
    Decorate with the raspberries, if using.
45. 45
    SERVING: Cut the cake into wedges, using a sharp, thin-bladed knife dipped in hot water and frequently wiped.
46. 46
    The cake needs no accompaniment.