Prep. Line a 12-cup muffin tin with paper liners. Preheat the oven to 425°F.

Whisk the dry ingredients. In a large bowl, whisk together 2 1/4 cups of the flour, the baking powder, baking soda, salt, and cinnamon.

Mix the wet ingredients. In a second bowl, whisk the melted butter and granulated sugar until combined. Whisk in the eggs one at a time, then the sour cream, milk, vanilla, and lemon zest until smooth.

Combine. Pour the wet ingredients into the dry and fold gently with a spatula just until no dry streaks remain. A few lumps are fine — overmixing makes tough muffins.

Add the berries. Toss the blueberries with the remaining 1/4 cup flour, then fold them into the batter gently.

Rest the batter. Let the batter rest at room temperature for 15 minutes. This hydrates the flour and gives you a taller, more tender muffin.

Fill and top. Divide the batter among the 12 cups, filling each to the very top (an ice cream scoop works perfectly). Sprinkle generously with coarse sugar.

Bake hot, then lower. Bake at 425°F for 5 minutes, then — without opening the oven — reduce the temperature to 350°F and bake 18 to 20 minutes more, until golden and a toothpick inserted in the center comes out clean or with moist crumbs.

Cool. Cool in the pan for 5 minutes, then transfer to a wire rack. These are incredible warm.