Begin by preheating your oven to 400 degrees F. Line a couple muffin pans with paper liners and set aside.
In a large bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.
In a medium bowl, whisk together the eggs and sugar until combined. Then whisk in the sour cream, oil, and vanilla extract.
Fold the wet ingredients into the dry and mix until almost combined.
In a small bowl, sprinkle 1 1/2 cups of blueberries with 1 tablespoon of flour and toss them until coated. (This will prevent the blueberries from sinking to the bottom of the muffins.) Then, gently fold them into your batter.
To make the streusel topping, mix together the flour, sugar, and cinnamon. Pour in the melted butter and stir with a fork until crumbly.
Scoop the batter into the prepared muffins tins, filling them about 2/3 full. Divide the remaining 1 cup of blueberries onto the top of each muffin. Then sprinkle each with the prepared streusel.
Place the muffin pan in the oven and reduce the heat to 375 degrees F. Bake for 20-24 minutes or until a toothpick inserted near the center of a muffin comes out clean.
Cool for 5-8 minutes in the pan. Then remove the muffins and allow them to finish cooling on a wire rack.