In the bowl of a stand mixer combine the warm water, sugar, and yeast.

Let sit about 5 minutes, until foamy.

Add the oil, egg, salt, onion soup mix, and 2¾ cups flour.

Using the dough hook, mix about 5 minutes until the dough becomes smooth and slightly tacky. Add additional flour if needed.

Cover the bowl and let the dough rise in a warm spot until doubled, about 90 minutes.

Punch down the dough and turn it onto a work surface. Divide into 8 equal pieces (about 3½–3.6 oz each).

Shape each into a smooth ball and place on a parchment-lined baking sheet.

Flatten slightly if using them for sandwich buns.

Cover loosely and let rise again until puffed, about 30 minutes.

Preheat oven to 375°F.

Brush the tops gently with the egg wash and sprinkle with the remaining onion soup mix. Press lightly so it sticks.

Bake 18–22 minutes, until lightly golden.

Let the rolls cool before slicing.