Speed up a breakfast classic by using store-bought baking mix -- it has all your baking staples (flour, leavener, and salt) in one box. Buttermilk and applesauce give these easy blueberry muffins a moist, tender crumb.
Preheat oven to 375 degrees. Line 12 standard muffin cups with paper liners; lightly coat liners with cooking spray.
Whisk together baking mix and sugar. In a large bowl, whisk together applesauce, buttermilk, eggs, oil, and vanilla. Fold in dry mixture until just combined, then gently fold in blueberries.
Divide batter evenly among cups, filling each to the brim. Bake until a toothpick inserted in center of a muffin comes out clean, 25 to 30 minutes. Let cool in pan 5 minutes, then remove from pan and let cool completely on a wire rack. Muffins can be stored in an airtight container at room temperature up to 3 days.