1. Heat oven to 425 degrees . In a small pot, bring 1/2 cup water, the butter, sugar and salt to a boil. Reduce heat to medium. Add flour and stir quickly until a ball of dough forms, about 1 minute. Remove to a bowl. Cool 5 minutes. Stir in eggs one at a time, until dough is smooth.
2. Transfer dough to a piping bag or resealable plastic bag with the corner snipped. Pipe twelve 11/2-inch mounds, spaced 2 inches apart, onto a parchment-lined baking sheet. Smooth out tops with a wet finger.
3. Bake at 425 degrees for 10 minutes. Reduce heat to 350 degrees and bake another 10 to 15 minutes, or until golden brown. Cool completely.
4. Slice each profiterole in half crosswise. Place a small scoop (about 3 tbsp) ice cream into bottom of each profiterole, then replace tops. Drizzle with chocolate sauce, if desired.