6 cups vegetable oil, or as needed, for frying
1 cup milk
1 cup water
1 large egg*
3 cups all-purpose flour
2 tablespoons baking powder
1 teaspoon salt
4 teaspoons sugar
2 firm bananas, peeled and cut into 1/2-inch-thick slices
Confectioners' sugar, for dusting
Pour oil into a deep pot to a depth of 3 to 4 inches. Heat oil to 370 degrees F.
Meanwhile, in a large bowl with an electric mixer on medium speed, combine milk, water and egg. Combine flour, baking powder, salt and sugar. Add slowly to milk mixture and mix until batter is smooth.
Fill a 2-tablespoon measure half full with batter, add a slice of banana and then fill the rest of the way with batter. Do not make them bigger as they will not cook through.
Drop formed beignet into hot oil and fry 3 to 4 minutes. When each beignet floats to surface, turn it and keep turning periodically until it's golden on both sides. Drain on paper towels. This will have to be done in batches.
While still warm, either roll beignets in confectioners' sugar or place sugar in a strainer and sprinkle over them. Serve hot.
*Break the egg in a separate bowl first to check for blood spots and discard it if it has a spot. This is how to check for a kosher egg.
Makes 20 to 24 beignets