Preheat oven to 350°.
In small bowl, beat cheese, confectioners' sugar and ReaLemon® brand until smooth; set aside.
Stir together flour, baking powder, baking soda and salt; set aside.
In large mixer bowl, beat granulated sugar and margarine until fluffy.
Add eggs and vanilla; mix well.
Add dry ingredients alternately with sour cream; mix well.
Pour half of batter into greased and floured 10-inch tube pan.
Spoon cheese mixture on top of batter to within 1/2 inch of pan edge.
Spoon remaining batter over filling, spreading to pan edge.
Sprinkle with Cinnamon-Nut Topping.
Bake 40 to 45 minutes or until wooden pick inserted near center comes out clean.
Cool 10 minutes; remove from pan.