In a mixing bowl, combine warm water, sugar, and active dry yeast. Let it sit for about 5 minutes until frothy.

In a separate bowl, mix all-purpose flour and salt. Add the yeast mixture and olive oil, then knead until smooth.

Allow the dough to rise in a warm place for about 1 hour, or until doubled in size.

Heat olive oil in a skillet over medium heat, add sliced onion, and sauté for 15-20 minutes until caramelized.

Add minced garlic and fresh spinach, cooking until wilted, around 2-3 minutes. Stir in nutritional yeast if using, and set aside.

Preheat your oven to 350°F (175°C). Roll out the dough to about ¼ inch thickness. Spread the filling evenly, leaving edges clear.

Roll the dough tightly from one end into a log, then cut into 1-inch pieces. Place seam-side down in a greased baking dish.

Cover with a towel and allow to rise for an additional 30 minutes in a warm area.

Bake for 25-30 minutes until golden brown and puffed up.

Let cool for about 5 minutes, then serve with marinara sauce for dipping.