Doughnut Muffins

3 cups all-purpose flour

2 1/2 teaspoons baking powder

3/4 teaspoon salt

1/2 teaspoon freshly ground nutmeg

1/4 teaspoon baking soda

3/4 cup whole milk, at room temperature

2 tablespoons buttermilk, at room temperature

10 tablespoons (1 1/4 sticks) unsalted butter, at room temperature

3/4 cup plus 2 tablespoons sugar

2 large eggs, at room temperature

Coating

1 cup sugar

1 tablespoon ground cinnamon

8 tablespoons (1 stick) unsalted butter, melted