Have your eggs and butter at room temperature before you begin baking. Line 24 muffin cups with paper bake cups. In a medium bowl stir together flour, cornmeal, corn starch, baking powder, and salt. Set aside.
Preheat over to 350 degrees. In a large mixing bowl beat butter with an electric mixer on high for 30 seconds. gradually add sugar, about 1/4 cup at a time, beating on medium speed for about 5 minutes or until light and fluffy. Beat in vanilla. Add eggs, one at a time, beating on low to medium for 1 minute after each addition making sure to scrape the sides of the bowl. Add flour mixture, stir until just combined.
Spoon batter into prepared muffin cups, filling each one 2/3 full. Sprinkle blueberries over batter in muffin cups. Sprinkle with streusel topping.
Bake for 15-18 minutes or until a toothpick inserted in center comes out clean. Cool cupcakes in pan for 10 minutes. Remove cupcakes from muffin cups and drizzle with vanilla icing.
Streusel Topping:In a medium bowl, combine flour, brown sugar, cinnamon, and salt. With a pastry blender or a fork, cut in the butter until mixture resembles coarse crumbs. Makes about 1 1/2 cups of topping.
Vanilla Icing:In a medium bowl, combine room temperature butter, powdered sugar, and vanilla. St ir in 1-2 tbsp of milk to make icing drizzling consistency. Makes approximately 3/4 of a cup.