Whisk together the flour, baking powder, salt, and cinnamon. Set aside.
250 grams all purpose flour, 1 tablespoon baking powder, ½ teaspoon fine sea salt, 1 ½ teaspoons ground cinnamon
Separately, beat together the butter, brown sugar, and granulated sugar until lighter in color and fluffy. About 2-3 minutes, scraping down the bottom and sides of the bowl as necessary.
113 grams unsalted butter, 133 grams light brown sugar, 67 grams granulated sugar
Add the eggs, vanilla extract, and the Natural Cinnamon Bun Artisan Flavor and mix on low speed until combined.
2 eggs, 1 tablespoon vanilla extract, ½ tablespoon Amoretti Natural Cinnamon Bun Artisan Flavor
Add half of the dry ingredients and mix on low speed until almost fully incorporated. With the mixer on low, add half of the yogurt and half of the milk and mix until almost incorporated. Repeat with the other halves of the dry ingredients and yogurt/milk.
120 grams plain greek yogurt, 60 grams whole milk
Cover the bowl tightly and let the batter rest at room temperature for 30 minutes.
While the batter is resting, preheat oven to 425F and line a jumbo muffin tin with liners leaving every other one empty. This will ensure the muffins bake evenly and form domed tops.
Make the cinnamon swirl/filling by mixing together the softened butter, brown sugar, and cinnamon until combined. Transfer the mixture to a piping bag.
113 grams unsalted butter, 100 grams light brown sugar, 1 tablespoon plus 1 teaspoon ground cinnamon
Once the batter is done resting, spoon the batter into the prepared muffin tin. Do not fold or whisk the batter before filling your tin - this will disrupt the work the leavening agents just did while the batter was resting.
Fill each muffin cup ¾ of the way to almost full. Cut the tip off of the piping bag with the filling to create a small opening. Pipe a swirl on the tops of each muffin, starting in the middle and working your way out. Put the piping bag aside - you will use the remaining filling later.
Bake the muffins for 8 minutes at 425F, then without opening the oven door, decrease the temperature to 350F and bake the muffins for an additional 13-16 minutes until a toothpick inserted into the center of the muffin comes out clean or with a few moist crumbs.
Let cool for 5 minutes in the muffin tin, then remove them onto a cooling rack and let cool for an additional 15-20 minutes.
Once cool enough to handle, use a sharp knife or cake dowel to poke a hole through the bottom of the muffin liner. Place the tip of your piping bag into the hole and pipe some of the brown sugar cinnamon filling into the muffin. Repeat with the rest of the muffins and enjoy!