Electric mixers may be of two basic types: Hand-held electric mixers quickly beat egg whites, whip cream, or blend light batters contained in separate bowls. Heavy-duty countertop mixers or other electric stand mixers, usually with stainless-steel bowls, assist in mixing stiff cookie doughs or large quantities of any dough or batter. A tree-shaped paddle attachment creams butter mixtures and smooths lumps without incorporating too much air into batters. A dough hook kneads yeast-leavened doughs in less time than it takes to knead the same dough by hand. To mix batters and doughs by hand, use a wooden spoon; for whipping egg whites and heavy cream, beat with a whisk.