Hi check this recipe for chocolate mousse cake recipe...
Rich Chocolate Mousse Cake
Yield: 8 servings
Ingredients
4 egg whites
½ cup (100 g) sugar
5 oz (140 g) hazelnuts, finely ground
2 tablespoons
unsweetened cocoa powder
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9 oz (250 g) dark
semi or bittersweet ch0ocolate (60-70%)
4 egg yolks
1/3 cup (60 g) sugar
¼ cup + 1 cup (0.6 + 2.4 dl) whipping cream
Cake - Preheat oven to 350 deg F (Gas mark 4 or 180 deg C).
- Line a 9 inch (23 cm) cake tin with greaseproof or other non-stick paper and grease the tin.
- Whisk the eggs whites until stiff and in peaks by using an electric mixer, gradually add the sugar and whisk well each time sugar has been added.
- Mix with finely ground hazelnuts and cocoa powder.
- Bake at 350 degrees for 15 minutes or until a wooden pick inserted in center comes out clean.
- Cool the cake.
Filling - Melt finely chopped dark chocolate over hot water.
- Beat the egg yolks with 2 oz sugar until white.
- Heat ¼ cup whipping cream to the boiling point, and whisk in beaten egg yolks.
- Fold in melted chocolate. The mixture will immediately thicken. Cool to approx. 100 deg F / 38 deg C.
- Whisk 1 cup of whipping cream. Fold with the egg and chocolate mixture, one tablespoon at a time until the filling becomes soft, then the remaining part of the cream.
- Transfer to the cake tin, and place in the refrigerator for several hours.
If served cold the filling appears more like chocolate truffle than mousse. If you prefer a more sweet flavor of the filling you can use semisweet chocolate (40-45%) instead of the recommended type.
Also, there are some nice cake recipes at the site in my sig that I use.
Looking For Chocolate Cake 
French chocolate cake 
