Prep the pan and oven: Heat the oven to 400°F (200°C). Line a 12-cup muffin tin with paper liners or grease lightly. A hotter oven helps create that nice muffin dome.

Whisk dry ingredients: In a large bowl, whisk the flour, sugar, baking powder, baking soda, and salt until well combined.

Add wet ingredients: To the same bowl, add the eggs, oil, yogurt, milk, vanilla, and lemon zest. Whisk gently until the batter is mostly smooth. A few small lumps are fine.

Fold in blueberries: If using frozen berries, do not thaw. Sprinkle 1 teaspoon of flour over the berries to help prevent sinking, then fold them into the batter with a spatula. Avoid overmixing.

Fill the muffin cups: Divide the batter evenly among the 12 cups, filling each about 3/4 full. For a crunchy top, sprinkle with coarse sugar.

Bake: Bake at 400°F (200°C) for 5 minutes, then lower the oven to 375°F (190°C) and bake another 12–15 minutes, until the tops are golden and a toothpick comes out clean or with a few moist crumbs.

Cool: Let muffins cool in the pan for 5 minutes, then transfer to a wire rack. They’re best slightly warm.