Combine the warm water, sugar, and active dry yeast in a large mixing bowl. Let the mixture stand for about 10 minutes, until the surface looks foamy.

Mix in the vegetable oil, egg, and salt until well combined. Add about 1 1/2 cups of flour first, stirring to make a thick batter.

Gradually add enough of the remaining flour to form a soft, workable dough. The dough should be slightly tacky but not wet, so stop adding flour as soon as it comes together.

Knead the dough by hand or with a dough hook for about 3-5 minutes, until it feels smooth and elastic. Avoid adding excessive flour, since a stiff dough can produce dense rolls.

Divide the dough into 12 portions and shape each piece into a smooth ball. Place the balls in a greased 9-by-13-inch baking pan with a little space between them.

Let the shaped rolls rest for 10 minutes while the oven finishes heating to 400°F (200°C). This brief rest helps the dough relax and puff slightly.

Bake for 10-12 minutes, until the tops are lightly golden. Brush the hot rolls with melted butter if desired, then serve warm.