Donut is an alternate spelling of doughnut. Some dictionaries point out that donut is rarely used outside the United States. All of them recognize doughnut as the main spelling, as do some of the more popular style guides. Doughnut might be the spelling you should use if you want to be sure you’re not making a mistake.-Grammarly
Fun Fact: 13 people have the first name “Donut,” making it the 245,396th most popular name in the United States.