Preheat oven to 350°F. Prepare a muffin tin with liners.
In a stand mixer, cream butter and sugar together. Add egg, sour cream, and vanilla.
1 stick unsalted butter, 1 egg, ¼ cup sour cream, 1 ½ teaspoons vanilla extract, 1 cup sugar
In a separate medium bowl, whisk together the flour, salt, baking soda and baking powder.
1 ⅔ cup all-purpose flour, ½ teaspoon baking powder, ½ teaspoon salt, ¼ teaspoon baking soda
To the wet ingredients, alternate adding dry ingredients and milk to the wet ingredients.
1 cup milk
Whisk slowly until the batter is smooth — do not over-mix.
Pour batter into lined muffin tin, filling cupcake liners about halfway full.
Bake for 18-21 minutes until cupcake centers bounce back to the touch. Allow the cupcakes to cool on a baking rack.
Meanwhile, make the buttercream frosting.
For the icing
Using a food processor, puree three large strawberries.
3 large strawberries
Add butter and vanilla to food processor. If food processor is big enough, add in powdered sugar ½ cup at a time. Use bowl and hand mixer, if not.
1 stick butter, ½ teaspoon pure vanilla extract, 3 cups powdered sugar
Once frosting is beginning to thicken, add in 1 tablespoon of heavy whipping cream.
1 tablespoon heavy cream
Icing should be smooth but hold its shape.
Pipe icing onto room-temperature cupcakes.
Notes
Tips & tricks
Use room temperature butter when mixing it with other ingredients. It will mix more thoroughly and more easily! Paper liners or silicone liners will make it easier to pull out your cupcakes. If you don't use liners, be sure to butter or spray your muffin tin generously so the cupcakes don't stick to the pan, which can cause them to break.
Substitutions
Plain Greek yogurt is a great 1:1 swap for sour cream. Don't omit this ingredient, it's the secret to super moist cupcakes!You can use a gluten-free 1:1 flour substitute to make this recipe without gluten. Replace the cane sugar in the cupcakes with coconut sugar to reduce the amount of refined sugar in this recipe. It may change the flavor and color a bit, but it will still be just as delicious!
Variations
You can add a little surprise in the middle of these cupcakes by removing the middle and adding a spoonful of strawberry jam or lemon curd to the center.