Cake: Set a rack in the middle of the oven and preheat to 350 degrees F.
Lightly coat 2 (9-inch) square cake pans with nonstick vegetable spray. Line the bottoms with baking parchment. In a large mixing bowl, sift the flour, baking powder, 1/4 teaspoon salt, and 1/2 cup of the sugar together 3 times. Stir in the matzo meal and chopped hazelnuts. Form a well in the center and add the oil, egg yolks, cream, hazelnut liqueur, and butter.
Mix until just blended.
In a clean, dry mixing bowl, whisk the egg whites with the pinches of salt and cream of tartar until creamy, foamy and barely able to hold peaks. While sprinkling on the remaining cup of sugar whisk until the consistency of stiff shaving cream.
Fold 1/3 of the egg whites into the yolk mixture, then fold in the remainder of the whites.
Spread the batter in the prepared pans and bake for 20 minutes or lightly tanned, the center springs back when lightly pressed and a cake tester comes out clean. Set the pans on a rack to cool. This cake is very delicate.
Remove from the pans, and trim even.
Place the cake onto a plate, parchment side up, and spread a layer of raspberry jam on the cut side of one layer. Flip the other layer on top and spread more jam on top.
Put the chocolate in a small bowl. Over medium heat, bring the cream to a scald.
Pour the hot cream over the chocolate. Working from the center out, gently stir with a whisk to melt and blend. Continue stirring until smooth.
