1In small bowl, combine all topping ingredients except margarine; mix well. With pastry blender or fork, cut in 3 tablespoons margarine until mixture resembles coarse crumbs. Set aside.
2Heat oven to 375°F. Grease 10-inch springform pan or 9-inch square pan. Sprinkle with bread crumbs. In large bowl, combine 2 cups flour, 1 cup sugar, baking powder, baking soda, salt and 1/2 teaspoon cinnamon; mix well. Stir in blueberries.
3Beat eggs in medium bowl. Stir in orange liqueur, 1/4 cup margarine, sour cream and orange peel. Add to blueberry mixture; stir just until dry ingredients are moistened. Spoon batter into greased pan. Sprinkle with topping.
4Bake at 375°F. for 35 to 45 minutes or until toothpick inserted in center comes out clean. Cool 10 minutes; remove sides of pan. Serve warm or cool.