Blueberry Sour Cream Coffee Cake

Grease a bundt pan. In a large bowl cream the margarine with 1 cup of sugar. Add the eggs. Sift the dry ingredients together and add to the egg mixture alternately with the sour cream. Pour half of the batter into the prepared pan and spread evenly. Combine 1/4 cup of sugar, the cinnamon, and vanilla. Spread half of the mixture onto the batter. Sprinkle with 1/2 cup of blueberries and 1/4 cup of walnuts. Spread on the remaining batter, cinnamon mixture, and fruit and nuts. Bake in a 350° oven for 50 to 60 minutes or until toothpick inserted in the center comes out clean.