Add enough oil to a deep fryer or large, deep heavy pot so that it is a couple of inches deep.
Heat the oil to 350 degrees.
Place 2 to 3 biscuits in the oil and allow them to lightly brown on one side, about 90 seconds. Be sure to fry only a couple at a time or the oil may cool too much and the donuts will absorb too much oil.
Turn the biscuits over to brown on the other side.
When the donuts are golden brown on both sides, transfer them to a wire rack or paper towels to drain for 15 seconds.
Pour sugar into a small bowl.
Dredge the warm donuts in the sugar.
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Recipe Tips
Tips for Perfect Chinese Donuts
Oil temperature is key: Maintain the oil at 350°F. If it's too hot, the outside will burn before the inside cooks; if it's too cool, the donuts will absorb too much oil and become greasy.
Don't overcrowd the pan: Fry in small batches to maintain oil temperature and give the donuts room to float.
Choose the right biscuits: Use the least expensive, regular (not flaky layers) canned biscuits for the most authentic texture.
Sugar while hot: Roll the donuts in sugar while they're still warm so the coating sticks better.