Typically, you make whipped cream just before you serve it—if it sits around it gets runny in no time. This make-ahead version, though, stays fluffy. You start by cooking some of the cream with cornstarch to create a paste. Cooled, this paste is whipped into the rest of the cold cream, stabilizing it for up to 3 days in the fridge or for a few hours out at room temperature. You can use this longer-lasting whipped cream in place of regular in pies (our Chocolate Mousse Pie, for instance), cakes (this White Cake with Lemon-Lime Curd is ideal), or good old Strawberry Shortcakes. This recipe makes enough whipped cream to frost 1 (8-inch) layer cake.