Line a greased jelly-roll pan, 15 1/2 by 10 1/2 by 1 inches, with wax paper, grease the paper, and dust the pan with flour, knocking out the excess. Into a bowl sift together the flour, the salt, and the baking powder and whisk in the almonds. In the bowl of an electric mixer beat together the egg yolks, 3/4 cup of the sugar, and the zest until the mixture is very thick and pale, beat in the lemon juice, the vanilla, and the almond extract, and beat the mixture for 3 to 5 minutes, or until it forms a ribbon when the beater is lifted. Add the flour mixture and beat the batter until it is just combined. In another bowl with cleansed beaters beat the egg whites with a pinch of salt until they form soft peaks, beat in the remaining 1/4 cup sugar, a little at a time, and beat the whites until they form stiff peaks. Whisk one third of the whites into the batter to lighten it and fold in the remaining whites gently but thoroughly. Spread the batter evenly in the prepared pan and bake it in the middle of a preheated 350F. oven for 15 to 20 minutes, or until the cake is golden and a tester comes out clean. Let the cake cool in the pan for 5 minutes, invert it onto a rack, and discard the wax paper. Invert the cake onto another rack and let it stand, uncovered, overnight to dry out. Cut the cake with a serrated knife into 3/4-inch cubes.

Serves 12.