Step 1

Preheat the oven to 350°F/175°C. Line a 12-cup pan with cupcake liners. This recipe makes 13-14 cupcakes.

Step 2

In a medium bowl, whisk together the flour, baking powder and salt.

Step 3

In a small bowl, combine the ½ cup of sugar and cinnamon for the cinnamon sugar swirl.

Step 4

In a stand mixer with the paddle attachment, beat the butter and sugar together on medium-high speed for 2 minutes. It should become light and fluffy.

Step 5

Add the eggs and vanilla extract, then beat again on medium speed

Step 6

Add in the sour cream, beating on medium-low speed until well combined

Step 7

With the mixer running on your lowest speed, add the dry ingredients

Step 8

With the mixer still running on low, slowly pour in the buttermilk. Stop the mixer.

Step 9

Use an ice cream scooper to fill each cupcake liner with 1 tablespoon of batter. Sprinkle over 1 teaspoon of cinnamon sugar, then another tablespoon of batter. Take a toothpick and swirl the batter together then sprinkle over another teaspoon of cinnamon sugar.

Step 10

Bake for 20-23 minutes. A toothpick inserted will come out clean with no crumbs. Let cool completely. Your cupcakes might have split at the top, almost like a muffin - this is ok!

Step 11

In a stand mixer fitted with the paddle attachment, beat the butter and brown sugar together on low speed until well combined.

Step 12

Slowly start adding the confectioners’s sugar on your lowest speed

Step 13

Increase the speed to medium-high and beat for a 2 minutes until it becomes very thick.

Step 14

Stop the mixer and add the salt, vanilla, and cinnamon in to the bowl. Beat on medium-high speed for another 2 minutes.

Step 15

Turn the mixer to your lowest speed and pour in the heavy cream. Beat until it becomes very creamy and spreadable.