This easy buttercream is thick enough to spread on cookies, but thin enough to melt over warm cinnamon rolls. If you’re looking for a shortcut frosting, this will be your new go-to. But if you want to kick it up a notch, try one of our three variations. The warm cardamom is fragrant, slightly citrusy and herbal. The pink peppercorn is fruity with a faint peppery bite. And the lemon is just the right side of tart, which helps balance the sugar. A pinch of salt in each helps accentuate the flavors. If you make the frosting ahead of time, press plastic wrap directly onto the surface and store at room temperature.