Place the blueberries in a bowl. Sprinkle 1 tablespoon of flour over them and gently toss to coat. (The flour will help keep the blueberries from sinking in the muffin as it cooks.)
Preheat your oven to 400°F with a rack in the lower middle. In a mixing bowl, whisk together the dry ingredients—the flour, baking soda, baking powder, and salt.
In a large mixing bowl, place the sour cream, sugar, eggs, milk, melted butter, lemon zest, and vanilla (the wet ingredients). Whisk together until smooth.
Add the dry ingredients to the butter/sugar/egg mixture a third at a time and mix until just incorporated. Do not over mix!
Gently fold the blueberries into the mixture.
Use a standard 12-well muffin pan. Place a muffin liner in each well of the muffin pan, or if you don't have muffin liners, grease the inside of the muffin pan wells with vegetable oil or butter. Distribute the dough equally among the cups. You'll need to fill them very high to use all of the batter in 12 muffins, which is fine. They won't spill. If you still have too much dough, start filling another tin.
Place the muffins in the oven and bake at 400°F until the muffins are golden brown, about 20 minutes. (If the muffins are getting too brown, tent with foil.) Test with a bamboo skewer to make sure the centers of the muffins are done. Let the muffins cool in the muffin pan for 2 to 3 minutes, then remove them from the pan. Let cool another 10 minutes before eating.
Read more: http://www.simplyrecipes.com/recipes/blueberry_muffins/#ixzz3ab0jkC00