In a large bowl, whisk together warm water, sugar, and yeast. Let stand for 5-10 minutes until foamy.

Stir in olive oil and salt into the yeast mixture.

Gradually add flour, mixing until a shaggy dough forms. Turn out onto a floured surface and knead for 8-10 minutes until smooth and elastic.

Place dough in a lightly oiled bowl, cover with plastic wrap, and let rise in a warm place for 1-1.5 hours, or until doubled in size.

In a skillet over medium heat, cook ground beef until browned. Drain off excess fat.

Add chopped onion and bell pepper to the skillet and cook until softened, about 5 minutes.

Stir in minced garlic and cook for 1 minute more until fragrant.

Add tomato sauce, oregano, salt, and pepper. Stir to combine and simmer for 5 minutes.

Remove from heat and let the filling cool slightly.

Preheat oven to 375°F (190°C). Line a baking sheet with parchment paper.

Punch down the risen dough and turn it out onto a lightly floured surface. Roll the dough into a large rectangle, about 12x18 inches.

Spread the cooled filling evenly over the dough, leaving a 1-inch border on all sides.

Carefully roll up the dough from one of the long sides, pinching the seam to seal.

Place the rolled dough seam-side down on the prepared baking sheet.

In a small bowl, whisk together the beaten egg and water for the egg wash. Brush evenly over the top of the dough.

Bake for 25-30 minutes, or until golden brown and cooked through.

Let cool for a few minutes before slicing and serving.