Super easy and super delicious, this chocolate frosting is sweet but not cloying, develops an outer layer but is still moist inside, has a great flavor, and comes together in minutes. It can be used as a filling too. A fantastic recipe!
Melt ½ cup unsalted butter and 3.5 ounces semisweet chocolate (as for brownies) in the microwave (short 5-second spurts and mixing well each time) or on top of a saucepan with hot water, being careful not to let it touch the bottom of the bowl.
Add sifted 1 tablespoon unsweetened cocoa powder and 2 cups powdered sugar in 2 parts and mix well until creamy.
Add 1 teaspoon vanilla extract or paste, a pinch of sea salt, and additional extracts if using.
Add ½ cup regular sour cream and mix very well. The final mixture should be creamy with no lumps.
Use directly as a frosting and/or filling. Keep refrigerated, covered.
Notes
Cocoa powder:Always use unsweetened. And, in my experience, the dark ones are the best (this does not apply to the super dark used for making homemade oreo cookies known as dark or black cocoa powder).Powdered sugar: Also called confectioners' sugar or icing sugar, there's no substitution for it. Regular sugar doesn't work.Refrigeration: This is the way to store it, in my opinion, as it keeps well for weeks in a tightly covered container. Whip it again before using it to achieve the best consistency.Freezing: You can freeze this chocolate frosting in a container that has a lid. I like to first put it in the refrigerator the night before so it defrosts gradually. Then take it out, bring it to room temperature and whip it again. It usually comes back together easily.