For Vanilla Cupcakes

1. Preheat oven to 350 degrees.
2. Line a 12 cup cupcake pan with liners and set aside.
3. In a medium bowl, sift together the cake flour, baking powder, baking soda and salt. Whisk to combine well. Set aside.
4. In the bowl of a stand mixer fitted with the whisk attachment, beat the butter and oil together on medium speed until well combined. There should be no lumps and the mixture will be light in color and smooth. This takes about 2-3 minutes.
5. Add the granulated sugar slowly, increasing the speed to high. Mix for 3 minutes, or until light and fluffy.
6. Add the eggs, one at a time. Stop the mixer to scrape down the sides after each addition, being sure to run the spatula along the bottom of the bowl.
7. Add the vanilla and beat on high speed for 3 more minutes. The mixture will be light and airy.
8. Add the dry ingredients to the egg mixture, alternating with the sour cream in 3 additions. Begin and end with the flour mixture.
9. Before the flour is fully mixed in to the batter, remove the bowl from the mixer and use a rubber spatula to finish combing the mixture. Do not over mix.
10. Use a 1/4 cup measuring cup to divide the batter evenly among the 12 cupcake liners, filling 2/3 full.
11. Tap the cupcake pan firmly on the counter two times to release any air bubbles.
12. Bake for 18-20 minutes or until the cupcakes are a light golden brown and a toothpick inserted into the center comes out with just a few crumbs remaining.
13. Remove the pan from the oven and cool the cupcakes in the pan for 5-10 minutes.
14. Remove the cupcakes from the pan and cool completely on a wire rack before frosting.

For Strawberry Buttercream

1. Wash and remove stems from the strawberries. Pulse in a food processor or blender until pureed. Set aside.
2. In the bowl of a stand mixer fitted with the whisk attachment, beat together the chilled butter and salt on medium high speed until light and fluffy, about 2-3 minutes. Stop to scrape down the sides of the bowl as needed.
3. Reduce the mixer speed to low and slowly add the confectioner’s sugar, 1/2 cup at a time.
4. Once incorporated, add the vanilla and whip on medium speed for 1-2 minutes more. Buttercream will be thick but smooth.
5. Add the strawberry puree and continue to whip on medium speed until combined.
6. Add the heavy cream, beating on medium low speed until fully combined.
7. If frosting is too thin, add more confectioner’s sugar. If too thick, add more heavy cream or strawberry puree. Buttercream should be slightly thick for piping swirls on to cupcakes.
8. Top each cupcake with a generous swirl of buttercream.
9. Serve fresh.