1 1/2 c. unsalted butter, softened
1 1/2 c. granulated sugar
2 oranges
1 1/2 tsp. Grand Marnier (orange liqueur)
8 eggs, separated, room temperature
2 c. sifted cake flour
1/2 tsp. salt
5 oz. semi-sweet chocolate bits

Cream butter in bowl. Gradually beat in all but 1/4 cup of sugar. Grate the oranges. Squeeze them and add enough orange juice to the zest to make 1/3 cup. Beat the orange juice and Grand Marnier into the butter mixture. Add the egg yolks, one at a time, beating thoroughly after each addition. Beat until the mixture is very light.

In a separate bowl, beat the egg whites until they form soft peaks. Add the remaining 1/4 cup of sugar and beat until the whites are stiff. Sift the flour and salt, 1/3 at a time, over the egg yolk mixture, folding it in after each addition. Stir in a quarter of the egg whites and fold in the remaining whites. Fold in chocolate bits.

Pour the batter into a greased and floured 10 inch Bundt pan. Bake at 350 degrees for about 1 hour or until toothpick comes out clean. Let cool 5 minutes before turning the cake out onto a wire rack.