• Prepare the cinnamon sugar layer. Melt the butter, stir in the brown sugar and cinnamon until thick. Set it aside to thicken while you make the muffin batter.
  3 Tbsp (43g) unsalted butter, ⅓ cup (71g) brown sugar, 1 ½ tsp cinnamon
• In a mixing bowl combine the properly measured flour (see notes), granulated sugar, baking powder, salt, cinnamon and nutmeg. Stir with a spoon to combine and set aside.
  3 ¾ cups (450g) all purpose flour, 1 ¾ cups (347g) granulated sugar, 3 tsp baking powder, 1 tsp salt, 1 tsp cinnamon, 1/4 tsp nutmeg
• In a larger mixing bowl combine the eggs, buttermilk, vegetable oil and vanilla extract. Stir to combine with a fork or spatula for 30 seconds. 
  2 large eggs, 1 ¼ cup (284g) buttermilk, ½ cup (100g) vegetable oil, 2 tsp vanilla extract
• Gradually mix in the dry ingredients, mixing by hand just until combined. The batter will be thick!
• Cover the bowl with a towel and allow the batter to rest for 15 minutes. During this time, preheat the oven to 425ºF.
• During the 15 minute rest, make the crumb topping. In a mixing bowl combine the flour, brown sugar, cinnamon, salt and melted butter. Use a spatula to mix the crumb. The mixture will be thick and you must stir well (elbow grease!) to combine all the dry ingredients. Continue to combine until the mixture looks wet. It’s okay if the mixture is “sandy” in texture. Use your hands to squeeze clumps together, forcing the mixture together. Set the crumb aside until ready to use.
  ¾ cup (90g) all purpose flour, ⅓ cup (71g) brown sugar, 1 tsp cinnamon, 1/4 tsp salt, ¼ cup (57g) unsalted butter
• For bakery style muffin tops, line a 12 count muffin pan with 6 muffins liners, meaning you’ll only fill every other muffin well with batter. Filling every other well allows the muffins to spread and dome without running into each other.
• Fill the liners with 2 tablespoons of batter. Drop 1 teaspoon of the cinnamon sugar mixture in the center of each muffin, use your fingers to spread it. Then add 4-6 tablespoons of batter, covering the cinnamon sugar. Remember, we want to fill the muffin cups full with batter!
• Take the crumb topping and crumble it into fine crumbs over each muffin, pressing it on slightly. Optional, sprinkle with sanding sugar.
• Place one pan in the center of the oven and bake for 7 minutes at 425ºF, then keep the muffins in the oven, and turn the temperature down to 350ºF and bake for 16-20 minutes* or until a toothpick inserted in the center comes out clean. Allow the muffins to cool in the pan for 15 minutes before removing. Repeat with the remaining batter, making sure to bump the temperature back up to 425ºF.

  *This bake time is based on the muffins having 6-8 tbsp of batter, if you add less batter, reduce the bake time.

Glaze (optional)

• In a small mixing bowl combine the powdered sugar, vanilla extract and milk. If the glaze is too thin, add more powered sugar 1-2 teaspoons at a time. Drizzle over the muffins.
  1/4 cup (28g) powdered sugar, 1/2 tsp vanilla extract, 1 tsp milk