- 1 cup water
- 8 tablespoons unsalted butter
- 3/4 teaspoon salt*
- 1 1/4 cups King Arthur Unbleached All-Purpose Flour
- 4 large eggs, at room temperature
- jelly, for filling
- granulated sugar or confectioners’ sugar, for coating
- *Use 1/2 teaspoon salt if you use salted butter.
- Combine the water, butter, and salt in a medium-sized saucepan, heat until the butter has melted, and bring to a rolling boil.
- Remove the pan from the heat, and add the flour all at once, stirring vigorously.
- Return the pan to the burner and cook over medium heat, stirring all the while, until the mixture smooths out and follows the spoon around the pan; this should take considerably less than a minute.
- Remove the pan from the heat, and let the mixture cool for 5 to 10 minutes. It’ll still feel hot, but you should be able to hold a finger in it for a few seconds. If you have an instant-read thermometer, the temperature should be below 125°F.
- Transfer the mixture to a mixer, and beat in the cinnamon, if you’re using it; then the eggs one at a time. The batter will look curdled at first, but when you add the last egg it should become smooth. Beat for at least 2 minutes after adding the last egg.
- Pour a generous 4 cups vegetable oil (peanut oil preferred) into a 10″ electric frying pan or heavy skillet set over a burner; the oil should be about 5/8″ deep. If you use a smaller or larger pan, add oil to a depth of between 1/2″ and 3/4″.
- Scoop small (1″) balls of batter into the hot oil, filling the pan but not crowding the doughnuts. A teaspoon cookie scoop, filled level, works well here.
- Fry the doughnuts for about 6 minutes. As they cook they’ll turn themselves over, usually multiple times. Use a chopstick or pair of tongs to give a nudge to any that seem to be stuck on one side. After about 6 minutes, the doughnuts should be a deep golden brown.
- Transfer them from the frying pan to a paper towel-lined baking sheet to drain and cool. Repeat with the remainder of the batter.
- Use a pastry bag equipped with a plain tip to pipe jelly into the interior of the cooled doughnuts. Shake them gently in a bag with granulated or confectioners’ sugar, if desired. Serve immediately; or wrap loosely and store at room temperature. The doughnuts will gradually soften as they sit.