Brown Sugar Butterscotch Cupcakes with Vanilla Frosting
Cupcakes:
- 1½ cups all-purpose flour
- ½ tsp. baking powder
- ¼ tsp. baking soda
- ¾ tsp. salt
- 1 cup brown sugar, lightly packed
- ½ cup butter, melted
- 1 large egg
- ¼ cup sour cream
- ½ cup milk
- 2 tsp. vanilla extract
Butterscotch Sauce:
- ¼ cup (½ stick) butter
- ¾ cup brown sugar
- ¾ cup heavy cream
- 2 tsp. vanilla extract
- ½ tsp. salt
Vanilla Frosting:
- 1 cup (2 sticks) butter, softened
- 3 cups powdered sugar
- 2½ tsp. vanilla extract
- 1–2 Tbsp. milk
- ¼ tsp. salt
Make the cupcakes: Preheat the oven to 350 degrees F. Line 10 – 12 muffin tins with cupcake liners and set aside. Whisk the flour, baking powder, baking soda, and salt in a medium bowl and set aside. In a small microwave-safe bowl, melt the butter. Pour the melted butter into a large (preferably heatproof since the butter will still be hot) bowl. Add the brown sugar and whisk until no lumps form. Add the sour cream, milk, vanilla extract, and egg and mix to combine. Gradually add the dry ingredients and mix with a rubber spatula until no lumps form.
Divide batter between the cupcake liners. Bake for 20 minutes, or until a toothpick inserted in the center comes out clean. Allow to cool completely before filling.
Make the butterscotch sauce: In a small saucepan, melt the butter. Add the brown sugar and whisk to combine. Whisk in the cream until the mixture is uniform and light brown, about 30 seconds. Leave to bubble and thicken for 5 minutes. Remove from heat and mix in vanilla and salt. Allow to cool.
Make the frosting: In the bowl of a stand mixer, cream the butter until fluffy. Add the powdered sugar one cup at a time until the frosting comes together (it will be very thick). Add the vanilla extract and mix, it should look smoother now. Add the milk, starting with 1 tablespoon and then slowly add more if needed (a little goes a long way!).
Assemble the cupcakes: Using a straw (or if you can’t find one, a toothpick may work, but not as well), poke a hole in each cupcake. Fill the hole with the butterscotch sauce, either using two spoons to let it seep into the hole or preferably, a squeeze bottle with a small tip if you have one. Let the sauce seep in for about a minute, since you will now be able to fit more sauce in the cupcake. Repeat for each cupcake. Fill a piping bag with the frosting and frost each cupcake.