The muffins are very moist and should be refrigerated if not eaten within 4 days other wise from personel experience they go green molded. It broke my heart to throw them out. I am going to try and make loafs next week.
Preheat oven to 375 degrees. Grease 16 muffin cups or line with paper muffin liners,
Beat butter and sugar in a large bowl until light and fluffy, about 3 minutes. Stir in eggs until well mixed. Add vegetable oil Stir to combine Whisk sour cream, milk and lemon zest into butter mixture until smooth.
Whisk flour, baking powder, baking soda and salt in a small bowl. Stir half the flour mixture into the butter mixture until combined, add remaining half of flour mixture and blueberries into batter, folding together until just combined.
Spoon batter into prepared muffin cups.
Place muffin cups on CENTER rack and bake until tops are golden and a toothpick inserted in the center comes out clean, about 30 minutes. ENJOY!