Buttermilk ice cream gets its ruby-colored swirls from fresh plums. Buttermilk-Plum Ice Cream Cook time: 5 hours Total time: 5 hours Ingredients 2 cups half-and-half 1 cup buttermilk 1 cup heavy cream 6 large egg yolks 1 1/3 cups plus 3 Tbsp. sugar, divided 2 cups peeled, chopped black plums (such as 'Methley') 1 tablespoon