1 tablespoon sugar
1 1/2 teaspoons cocoa
2 ounces softened cream cheese
1 1/2 teaspoons hazelnut liqueur or rum
2/3 cup flour
1/4 cup cocoa
1/2 teaspoon baking powder
1/8 teaspoon baking soda
1/4 cup water
1 tablespoon hazelnut liqueur or rum
1/4 cup softened butter
2/3 cup sugar
1/2 teaspoon vanilla extract
1 egg yolk
1 egg white

Heat oven to 350°F. Grease and flour 11x4 inch (4 cup) nut bread pan. Stir together sugar, cocoa and cream cheese. Stir together flour, cocoa, baking powder and baking soda. Stir together water and liqueur. Beat butter on medium speed 30 seconds. Add sugar and vanilla till well mixed. Add yolk and beat on medium speed 1 minute. Alternately add dry mixture and water mixture to creamed mixture, beating after each addition till just combined. Beat egg white to stiff peaks and gently fold into batter. Spoon 1 cup batter into prepared pan, spreading evenly. Carefully spoon chocolate filling in a row down center of batter in pan. Top with remaining batter, spreading evenly. Bake 30 minutes till toothpick inserted in center comes out clean. Cool in pan on rack 15 minutes before turning out onto rack to cool completely.
Nicole's Note
I don't know what a nut bread pan is. I'm not sure this is really a truffle cake. I think the name may be wrong.