If you don't have a thermometer, heat the oil until it bubbles when you place the handle of a wooden spoon in it. Then, add a single donut or single donut hole to test the temperature of the oil. u003cbr/u003eFry the donut completely until it's golden brown on the outside, then cut it in half. If it's cooked through and not raw in the middle, you have a good temperature for frying donuts. If it's raw in the middle, lower the temperature of the burner and wait a few minutes for the oil to cool slightly before trying again. If it takes longer than 2–3 minutes per side to fry the donuts, raise the temperature of the burner and wait a few minutes for the oil to warm up.