Step 1

Place 1 stick unsalted butter in the bowl of a stand mixer (or large bowl if using an electric hand mixer). Let sit at room temperature until softened. Meanwhile, coat a standard 12-well muffin pan generously with cooking spray, or line with paper liners.

Step 2

Arrange a rack in the middle of the oven and heat the oven to 400ºF.

Step 3

Place 3 tablespoons unsalted butter in a small microwave-safe bowl. Microwave on high until melted, about 30 seconds. (Alternatively, melt in a small saucepan over medium heat.) Place 1/4 cup granulated sugar, 1/2 teaspoon ground cinnamon, 1/8 teaspoon ground mace or nutmeg, and 1 pinch kosher salt in a small bowl and stir to combine.

Step 4

Place 2 cups all-purpose flour, 1 1/4 teaspoons kosher salt, 1 teaspoon baking powder, 1/2 teaspoon baking soda, and 1/2 teaspoon ground mace in a medium bowl and whisk until combined.

Step 5

Add 3/4 cup granulated sugar to the bowl of butter. Beat with the paddle attachment on high speed until pale colored and fluffy, about 2 minutes. Beat in 2 large eggs, one at a time, scraping down the sides of the bowl after each addition. Add 1 cup sour cream and 1 1/2 teaspoons vanilla extract and beat until combined.

Step 6

Add about 3/4 of the flour mixture to the butter mixture. Fold in by hand with a rubber spatula until just combined (a few traces of dry flour are okay). Add the remaining flour mixture and stir until just combined, do not overmix.

Step 7

Divide the batter evenly between the muffin wells (they will be very full). Brush the top of each muffin generously with the melted butter. Sprinkle with the sugar-cinnamon mixture (scant 1 teaspoon per muffin). It will look like a lot of topping, but that’s a good thing.

Step 8

Bake for 8 minutes. Do not open the oven door and reduce the oven temperature to 350°F. Bake until a toothpick inserted into the center of a muffin comes out clean, 8 to 10 minutes more (dark pans will bake more quickly). Let the muffins cool in the pan for 5 minutes. Remove the muffins from the pan and serve warm or transfer to a wire rack to cool completely.