Put the butter, water, sugar, and salt in a medium saucepan over a medium/high heat. Whisk until the butter melts and the sugar dissolves. Bring to a boil.

Once boiling remove from heat. Add in the flour and use a wooden spoon to mix until no flour is visible. Return to the flame and mix until smooth.

Add hot dough to the bowl of an electric stand mixer fitted with the whisk attachment. Add one egg at a time and mix on medium/high until the egg is combined. continue the process with the 2 remaining eggs and egg yolk. Let the dough come to room temperature.

Add about 2-3 inches deep of oil to a large Dutch oven. Heat over a medium/high flame until a candy thermometer inserted into the center reads 375 degrees F.

Drop about 4 tablespoon sized dollops of batter into the hot oil. Fry the four zeppole at a time for about 5-6 minutes, flipping back and forth a few times, until deeply golden and puffed.

Once cooked, transfer the zeppole to a paper towel lined baking sheet. Dust with powdered sugar. Continue to fry until all the batter is used.

Eat once slightly cooled.