Preheat the oven to 200 degrees, grease a muffin tin or line it with paper liners. Mix the flour, baking soda, baking powder, sugar and salt. Mix together the melted butter, egg and sour cream with a whisk. Add the flour mixture and stir in.
Put the blueberries in a bowl and mix with the teaspoon flour, then stir into the batter. Put one tablespoon at a time into the prepared muffin pan, it is a slightly firmer batter. Place in the preheated oven and bake for about 20 minutes, until they are light in color and firm when you press down on the center.