Preheat the oven to 425 degrees and prepare a muffin pan by lining it with muffin liners.
Mix together the sugar, melted butter, nutmeg, and cinnamon in a large bowl.
1 cup sugar, 1/2 cup unsalted butter, 1 tsp ground nutmeg, 1 tsp ground cinnamon
Stir in the buttermilk and vanilla until just mixed in.
1 cup buttermilk, 2 tsp vanilla extract
Add the flour, baking soda, and salt. Mix again until the wet and dry ingredients are just mixed together.
2 cups cake flour, 1 tsp baking soda, 1 tsp salt
Let the batter sit out at room temperature for 15 minutes.
Add about 3 to 4 tablespoons of batter into each muffin tin.
Put the muffins into the preheated oven and bake for 7 minutes. Then reduce the temperature down to 375 degrees and finish baking the muffins for 12 to 15 minutes. Muffins are done when a toothpick comes out clean.
Cool muffins in the muffin pan for 20 to 30 minutes.
In the bowl of a stand mixer mix together the powdered sugar, vanilla, and half and half until they are fully mixed and smooth.
If you want to make mini cinnamon sugar donut muffins, fill mini muffin tins completely then bake 8-10 minutes or until a toothpick comes out clean. Mini cinnamon sugars are a great little snack for kids!Make the right amount of topping. The glaze and cinnamon sugar amounts written in the recipe are enough to drizzle 12 muffins each, reduce them by half if doing both on one batch. Be sure your ingredients start at room temperature. If you forgot to let your buttermilk get to room temperature, you can warm it up in the microwave for 15 seconds before adding to the recipe.Make a buttermilk substitute. If you forgot to go out and buy buttermilk, you can substitute it with lemon juice and whatever milk you have on hand.Let the batter sit. The muffins need to rest at room temperature before baking to keep the moist texture of the muffin crumb after baking!