1 Tbsp heavy cream (for a fluffier frosting; skip if it needs to be structural)
1 tsp vanilla extract
3½-4 cups powdered sugar
1/3 cup seedless raspberry preserves
½ tsp citric acid, to taste (optional)
Cream the butter, add cream, vanilla, and powdered sugar until well combined. Mix in the preserves. Add the citric acid a bit at a time, tasting as you go. The flavor of this will develop as it dissolves, so don't go overboard unless you want it really tart.
Without the acid, this frosting is still good, but more delicate (raspberry-scented, if you will).
