For the dough: Bring 250 ml (approximately 1 cup) of water with the butter and salt to a boil. Add the flour all at once to the liquid and stir. stir until a shiny ball has formed in the middle of the pot and the bottom of the pot is coated with a white skin. Transfer the dough to a mixing bowl.
Mix the sugar with the baking powder and knead with a dough hook or paddle. Gradually add the eggs and process into a smooth, shiny, dough.
To finish: In a wide pot, heat a large amount of vegetable oil to 170°C (approximately 350°F). Form the dough into small balls and fry in portions for 2-3 minutes until golden brown. Drain on paper towels and serve immediately, dusted with powdered sugar.