The bake time for jumbo muffins is 20 to 25 minutes in an oven set to 400 degrees. After the extra-large muffins are taken out of the oven, they’ll need to cool for 15-20 minutes before eating so they have time to settle; remember, cooking doesn’t stop once the muffins are taken out of the oven. The bake time for large muffins differs from standard-sized muffins that only need about 15 minutes to cook. To test for doneness, insert a toothpick or cake tester into the center of the muffin and see if it comes away clean. A few crumbs are ok, but there shouldn’t be any wet batter.