Homemade doughnuts are best enjoyed fresh on the day they are made. However, if you have leftovers, store them in an airtight container at room temperature for up to 2 days. For longer storage, you can freeze the doughnuts in a freezer-safe bag or container for up to 2 months. Thaw frozen doughnuts at room temperature or reheat them briefly in the oven before serving.