Rehrucken means "saddle of venison"; it refers to the shape of the loaf pan used to make these traditional Austrian cakes.
Heat oven to 350 degrees. Spray 3 rehrucken pans (11 3/4-by-4 1/2-inch loaf pans can be used instead) lightly with vegetable-oil spray. Scatter almonds in pans. In an electric mixer, beat butter, almond paste, confectioners' sugar, salt, vanilla, and lemon zest on medium-low speed, about 1 minute. Add egg yolks, one at a time, beating on medium-low speed for 1 minute after each. Beat in liqueur.
In a medium bowl, sift together cornstarch and flour.
Beat egg whites on medium-high speed until foamy, about 2 minutes. Gradually add granulated sugar and beat on high speed until stiff peaks form, about 6 minutes.
Using a rubber spatula, fold half of the flour mixture into the egg-yolk mixture. Fold in half the egg whites. Fold in remaining flour mixture, then remaining egg whites, then chocolate and ginger.
Divide batter evenly among 3 pans. Bake for 25 minutes, rotate pans between ovenshelves, and bake about 25 minutes more; a cake tester inserted into the center of each loaf should come out clean. Let pans cool on a wire rack for about 5 minutes. Transfer loaves from pans to rack; let cool 20 minutes. Serve warm or at room temperature.