The first step is to preheat the oven to 400°F (200°C).
Prepare muffin cups by either greasing them or lining them with paper baking cups.
In a sizeable mixing bowl, combine Bisquick mix and sugar.
Combine egg, milk, and vegetable oil in a separate bowl and mix until thoroughly incorporated.
Pour the liquid components into the solid ones and stir them delicately until they are thoroughly incorporated.
Softly blend the blueberries into the mixture.
Pour the batter into the muffin cups, leaving some room for rising during baking.
Allow to bake for roughly 15-20 minutes, or until a toothpick can be inserted in the center and removed without any batter sticking to it.
Let the muffins cool off for 5 minutes in the pan, then take them out and put them on a wire rack to cool down fully.