Preheat the oven to 400°F. Butter a muffin tin and set aside. In a small bowl, toss ¼ cup of the flour with the blueberries and set aside. In a large mixing bowl, combine the remaining 1¾ cups flour, sugar, baking powder, and salt. Using a wooden spoon, blend in the buttermilk, eggs, and melted butter.

Fold in the lemon zest and vanilla and mix just until smooth. Gently fold in the blueberries. Fill the muffin cups two-thirds full.

Bake for 20 minutes, or until golden brown. Cool on a wire rack for 2 to 3 minutes before removing from the pan. Serve the muffins warm.