01 -
Preheat oven to 350°F and line a 12-cup muffin tin with cupcake liners.
02 -
Whisk all-purpose flour, baking powder, baking soda, ground cinnamon, and salt in a medium bowl.
03 -
In a large mixing bowl, cream softened butter and granulated sugar together with a mixer on medium speed until light and fluffy, about 3–4 minutes.
04 -
Add eggs one at a time, beating well after each addition. Stir in vanilla extract.
05 -
Alternate adding dry ingredients and sour cream to the butter mixture, starting and ending with dry ingredients. Mix until just combined.
06 -
Gently mix in the whole milk until the batter is smooth and fully incorporated.
07 -
In a small bowl, combine brown sugar and ground cinnamon. Drizzle in melted butter and stir until it forms a thick paste.
08 -
Spoon a heaping tablespoon of batter into each cupcake liner. Top with a small spoonful of cinnamon-sugar mixture. Swirl gently with a toothpick or small knife.
09 -
Add another heaping tablespoon of batter to each liner, filling about two-thirds full.
10 -
Bake in preheated oven for 18–22 minutes, or until a toothpick inserted into the center comes out clean.
11 -
Let cupcakes cool in the tin for 5 minutes, then transfer to a wire rack to cool completely.
12 -
Whisk powdered sugar, milk, and vanilla extract together in a small bowl until smooth.
13 -
Once cupcakes are fully cool, drizzle glaze over each. Allow glaze to set before serving.