Preheat oven to 325 degrees.
Cream butter and 2 cups sugar. Add egg yolks, one at a time, beating well after each addition. Sift flour, baking soda and salt twice. Add to creamed mixture, alternating with sour cream. Beat egg whites and remaining cup of sugar until stiff. Fold gently into batter. Blend in flavorings.
Bake in a greased and floured tube pan 1 1/2 hours at 325 degrees.
Cake should have a nice, brown crust.
Let stand 15 minutes before removing from pan.
Note: To coat pan, the former first lady uses 1 tablespoon flour and 1 tablespoon confectioners' sugar mixed together.