Boil water, butter, sugar, and salt together in a saucepan. Add flour and work it in until it is all incorporated and dough forms a ball. Transfer mixture to the bowl of a standing mixer and let cool for 3 to 4 minutes. With mixer lowest speed, add eggs, 1 at a time, making sure the first egg is completely incorporated before continuing. Once all eggs have been added and mixture is smooth, put dough in a piping bag fitted with a number 12 tip. Heat about 1 1/2 inches of oil in a heavy pan. Pipe dough into oil, making a free-form lattice pattern; cook until browned, flipping once. Remove cake from oil, drain on paper towels, and top with powdered sugar. Continue until all of the batter is used.