Cinnamon swirl biscuits are easy, buttermilk drop biscuits that have a sweet cinnamon sugar swirl throughout. They taste like biscuit cinnamon rolls but are so much quicker and easier to make!
Adjust oven rack to middle position and preheat oven to 475 degrees F. Line a rimmed baking sheet with parchment paper. Set aside.
Melt the butter in a large, microwave-safe bowl in the microwave until about 90% melted.
Whisk until completely melted.
Let the butter sit for 5 minutes to cool slightly.
Whisk in the cold buttermilk. The butter should clump up.
Add the flour, baking powder, baking soda, sugar, and salt. Whisk just until combined. Don't overmix.
In a small dish, whisk together the cinnamon and sugar.
Pour the cinnamon sugar mixture over the biscuit dough, and give it a couple of folds. The cinnamon sugar should still be visible in swirls and shouldn't be completely incorporated.
Drop ¼-cup scoops of biscuit batter about 2 to 3 inches apart on the prepared baking sheet.
Bake for about 12-15 minutes, or until light golden brown.
To make the icing, melt the remaining butter in a medium microwave safe dish.
Whisk in the powdered sugar a little at a time.
Add enough milk to form a glaze that can be drizzled but is still thick.
Whisk in the vanilla extract.
Drizzle the biscuits with the icing and serve warm.
Notes
Butter: I use salted butter. Feel free to use unsalted butter if you prefer.
Buttermilk: I like to use full-fat buttermilk for softer, richer biscuits.
Cinnamon swirl: I've doubled the cinnamon swirl portion. If doubling the cinnamon swirl portion, be careful about the baking time as the additional sugar causes the biscuits to brown faster.