Preheat your oven to 375°F (190°C) to ensure even baking.
Grease the muffin tin or line it with muffin liners.
In a large mixing bowl, combine the homemade Bisquick mix, granulated sugar, and brown sugar. Whisk until well blended.
Cut the cold butter into small cubes and add to the dry ingredients. Mix until the mixture resembles coarse crumbs.
In another bowl, whisk together the milk, melted butter, egg, and vanilla extract until smooth.
Pour the wet ingredients into the dry ingredients. Stir until just combined, being careful not to overmix.
Gently fold in the blueberries until evenly distributed.
Spoon the batter into the prepared muffin tin, filling each cup about 2/3 full.
Bake in the preheated oven for 18-20 minutes, or until a toothpick inserted comes out clean.
Allow the muffins to cool in the tin for about 5 minutes before transferring to a wire rack.