Preheat the oven to 375°F and put an oven rack in the middle position. Line a 12-cup muffin tin with paper liners. If not using liners, spray the tin generously with non-stick spray.
Clean blueberries and keep them dry. Dust with 2 tablespoons of flour and keep aside.
In a big mixing bowl whisk together sour cream and eggs until creamy. Then add melted butter, oil, milk, vanilla extract, and lemon zest and mix.
Add sugar to the wet mixture. Place a sieve on top of the bowl. Add flour, baking powder, baking soda, and salt. Sieve the dry ingredients directly to the wet mixture ( otherwise mix all dry ingredients in a bowl and add to the wet mixture)
Mix the dry ingredients using a spatula. Don't overmix. A few pockets of dry flour is fine.
Fold in the flour dusted blueberreis.
Using an ice cream scoop, divide the mixture equally in a muffin tin. Fill only 3/4th of the space. You should get 12 regular-sized or 8-9 extra large muffins.
Sprinkle 1/2 teaspoon sugar on top. You can also top it with 2-3 extra blueberries.
Bake it for 15-20 minutes or once the top looks golden in colour and the toothpick comes out clean.