Grease and flour two 8x1-1/2-inch round baking pans. In a sieve, rinse and drain sauerkraut. Snip finely; set aside.
In a bowl, combine flour, cocoa powder, baking soda, and salt.
In a large bowl, beat sugar, butter, and vanilla with an electric mixer until well combined. Add eggs, beating after each addition. Add dry ingredients alternately with coffee, beating until just combined. By hand, stir in sauerkraut. Turn into prepared pans.
Bake in 350 degree F oven 30 to 35 minutes or until wooden pick inserted in centers comes out clean. Cool in pans 10 minutes. Remove; cool. Fill and frost with Chocolate-Sour Cream Frosting. Makes 12 servings.
In a heavy saucepan, over very low heat, melt milk chocolate, chopped. Cool for 10 minutes. Stir in dairy sour cream. The mixture may stiffen at first, but will become smooth as you stir in all the sour cream.