Cupcakes:

1. Preheat oven to 350 degrees. Line a 12-cup muffin tin with paper liners.
2. In a medium bowl combine flour, baking powder, and salt.
3. In a separate bowl combine sour cream, milk, and eggs.
4. In a large bowl or standing mixer, beat the melted butter, sugar and lemon zest until well combined; about 2 minutes. Add the lemon juice and beat for another minute. Slowly add the flour mixture, beating until just combined. Add in sour cream mixture and beat on low until just combined.
5. Pour cupcake batter evenly into the prepared muffin tin. Bake for 17-10 minutes, or until a toothpick inserted into the center of a cupcake comes out clean. Allow cupcakes to cool completely before frosting.

Raspberry Buttercream Frosting:

1. In a small saucepan, simmer the raspberries and lemon juice. Stir together over medium heat until the mixture is smooth, resembling jam. Remove from heat and allow raspberry puree to cool completely.
2. In a large bowl or standing mixer, cream the softened butter until light and fluffy. Add the raspberry puree and beat until completely combined; about 1 minute. Add powdered sugar, one cup at a time, on low speed. Add the cream and salt, beating on high-speed until the frosting is fluffy.
3. Frost cupcakes and top with raspberries.