01 -
Preheat the oven to 375°F. Line a 12-cup muffin tin with paper liners or lightly grease each cup.
02 -
In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, baking powder, baking soda, and salt until uniformly blended.
03 -
In a separate bowl, whisk the melted and cooled butter with eggs, buttermilk, vanilla extract, and lemon zest, if using, until smooth.
04 -
Pour the wet mixture over the dry ingredients and gently fold together with a spatula or wooden spoon. Do not overmix; a few small lumps are acceptable.
05 -
Carefully fold in the blueberries, distributing them evenly throughout the batter.
06 -
Spoon or scoop the batter into the muffin cups, filling each about two-thirds full. Sprinkle tops with coarse sugar, if desired, for added texture.
07 -
Place the muffin tin in the preheated oven and bake for 20 to 25 minutes, or until the tops are golden and a toothpick inserted in the center of a muffin emerges clean.
08 -
Let the muffins rest in the tin for 5 minutes, then transfer to a wire rack to cool completely. Serve warm or at room temperature.