Preheat oven to 400˚F.
Melt butter in water on stove top, then shut off heat.
Add flour and salt; mix well.
Add eggs; mix well.
Drop spoonfuls of batter onto baking sheet about 2 inches apart.
Bake for 35 minutes.
Once cool, cut puffs in half horizontally and fill with filling. Sprinkle with sifted powdered sugar.