Preheat the oven to 375°F (190°C). Line a muffin tin with paper liners or grease the cups lightly with butter or cooking spray.

In a large bowl, whisk together the flour, granulated sugar, brown sugar, baking powder, and salt until well combined.

In another bowl, mix the melted butter, eggs, milk, vanilla extract, and lemon zest until smooth.

Pour the wet ingredients into the dry ingredients and gently fold together until just combined. Do not overmix; a few lumps are fine.

Toss the blueberries with 1 tbsp of flour to coat them lightly. This helps prevent them from sinking to the bottom of the muffins.

Gently fold the blueberries into the batter, being careful not to crush them.

Divide the batter evenly among the muffin cups, filling each about 2/3 full.

Bake for 18-20 minutes, or until a toothpick inserted into the center of a muffin comes out clean.

Let the muffins cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.