Add the vanilla extract, lemon juice, lemon zest, sour cream and oil and beat until combined. Add the flour mixture and beat until incorporated. Fold in the blueberries.
Spoon the batter into muffin cups. Bake in preheated oven at 350 ºF for 25-30 minutes or until a toothpick inserted in the center of a muffin comes out clean. Remove from the oven and allow to cool completely.