Preheat the oven to 325ºF. Lightly grease your muffin pans or use muffin pan liners.
Mix 2 cups Bisquick, sugar, melted butter, egg, and lemon extract in a large bowl until just combined.
Gently fold the blueberries into the muffin batter.
Fill the muffin pan wells 3/4 full of the blueberry muffin batter. Bake for 20-25 minutes.
Serve warm with butter.