Stir together oats, brown sugar, and 1/2 teaspoon cinnamon; set aside.
Beat butter and granulated sugar at medium speed with an electric mixer until fluffy. Add egg substitute, beating until blended. Stir in vanilla.
Combine all-purpose flour, baking soda, baking powder, salt, and remaining 1/2 teaspoon cinnamon; add to butter mixture alternately with buttermilk, ending with flour mixture. Gently stir in blueberries. Spoon batter into muffin pans coated with cooking spray, filling two-thirds full. Sprinkle evenly with oat mixture.
Bake at 350° for 15 to 20 minutes or until tops are golden. Cool muffins in pans 5 minutes; remove from pans, and cool on wire racks.