how long can buttercream icing sit out
Most buttercream icings made with butter and egg whites or egg substitutes -- called meringue buttercreams â perform best at room temperature. They can be kept out for up to three days â either in a bowl or on a cake -- covered or in a cool, dry place. Butter begins to separate at temperatures between 88 and 98 degrees Fahrenheit. This is not a health concern, but on a hot day, your buttercream can slide off the cake if the fat separates from the whey.