Preheat oven to 375°F. Make sure your oven is fully preheated before putting anything in — this ensures even baking from the very first minute.
Mix flour, sugar, baking powder, and salt. Always taste as you go — you can add more seasoning, but you can't take it away!
Whisk eggs, milk, butter, lemon zest, and juice.
Gently fold wet into dry ingredients.
Fold in blueberries.
Fill muffin cups 3/4 full.
Bake 18-20 minutes until golden. Every oven is a little different, so start checking a few minutes early. You're looking for a golden color and a wonderful aroma filling your kitchen.
Cool in pan 5 minutes. I know it's tempting to dig in right away, but this resting time allows everything to set properly and makes a real difference in the final result.