1. In large bowl, with mixer at high speed, beat egg whites and cream of tartar until soft peaks form. Beating at high speed, sprinkle in sugar, 2 tablespoons at a time, beating until sugar is dissolved and whites stand in stiff peaks.
2. Preheat oven to 325°F. In another large bowl, with mixer at low speed, beat egg yolks, flour, and remaining ingredients except walnuts until blended, scraping bowl often with rubber spatula. Stir in walnuts. Fold flour mixture into beaten egg whites just until blended.
3. Pour batter into ungreased 10-inch tube pan. Bake 1 hour and 15 minutes or until cake springs back when lightly touched. Invert cake in pan on funnel or bottle; cool completely in pan. With metal spatula, carefully loosen cake from pan; place on cake plate.