In a mixing bowl, whisk together the flour, baking powder, and salt. Set aside.
In another bowl, combine melted butter and sugar, whisk until mixed. Add eggs, vanilla, sour cream, and milk, whisk until integrated.
Gently stir the dry ingredients into the wet mixture until just combined. Cover and refrigerate for 30 minutes to overnight.
Preheat oven to 375°F (190°C) and line muffin pans with cupcake liners.
Prepare cherries by washing, pitting, and chopping if fresh, or chop frozen cherries without thawing.
Fill each muffin liner with batter using a cookie scoop, sprinkle coarse sugar on top if desired.
Bake for 18-22 minutes until golden brown and a toothpick comes out with a few moist crumbs. Cool in the pan for 5 minutes before transferring to a wire rack.