Preheat oven to 375°F with racks in upper and lower thirds

Melt 2 sticks of butter in a saucepan over low heat for pan preparation and dunking

Mix together 2 cups plus 2 tablespoons flour, 1½ teaspoons baking powder, 1 teaspoon baking soda, 1 teaspoon kosher salt, and a pinch of nutmeg

Prepare cinnamon sugar by mixing 1 cup granulated sugar, 1 tablespoon ground cinnamon, and a pinch of salt

Butter and flour 1½ muffin tins using a pastry brush

In a stand mixer with paddle attachment, beat 2 sticks room temperature butter with ¾ cup granulated sugar on medium speed until very pale and fluffy

Add 2 eggs one at a time on medium speed, waiting for each to incorporate

Add 2 teaspoons vanilla extract

Alternate adding dry ingredients and sour cream on low speed: one-third flour, half sour cream, half remaining flour, remaining sour cream, final flour

Complete final mix by hand with a flexible spatula to prevent over-beating

Portion batter into prepared muffin cups using a 2 oz scoop, filling each cup scant full

Bake for 20-25 minutes, rotating pans after 15 minutes, until muffins are domed, golden brown, and springy to the touch

Cool muffins for 2 minutes, then unmold onto a cooling rack

While still hot, quickly dunk each muffin into melted butter, coating all surfaces

Immediately roll each buttered muffin in cinnamon sugar, coating completely

Serve warm