Preheat oven to 350°F. Line a standard 12-count muffin tin with paper liners, if desired, or spray the pan with nonstick spray. Set aside.
Whisk the milk, eggs, oil, and vanilla extract in a large bowl.
¾ cup milk, 2 large eggs, ¼ cup vegetable oil, 2 teaspoons pure vanilla extract
Add the pancake mix and sugar and whisk until combined.
2 cups dry pancake mix, ⅓ cup granulated sugar
Option One: Stir the blueberries into the batter. Then fill each muffin cup ¾ full.
¾ cup fresh blueberries
Option Two: Fill each muffin cup with 2 tablespoons of the batter, filling about ⅓ of the way full. Add 1 tablespoon of the blueberries onto the batter. Top the blueberries with an additional 2 tablespoons batter, filling each cup about ½-inch from the top of the liners. Stir the batter with a toothpick.
Bake for 18-23 minutes, or until a toothpick inserted comes out clean.