Prepare Onions: Cut white onions into julienne slices, coat with flour and starch, and strain.
Fry Onions: Heat oil in a pan and fry the onions until golden brown.
Make Daqqa: In a pot, sauté garlic in onion oil, add vinegar, and then mix with lemon, water, salt, cumin, and coriander.
Prepare Sauce: Blend tomatoes and add to the garlic and vinegar mixture, season with salt, pepper, and broth.
Cook Rice and Vermicelli: In a pot, sauté vermicelli in onion oil, add rice, and stir well.
Boil Lentils: Cook lentils in boiling water with salt, cumin, and coriander for about 10-15 minutes.
Combine Ingredients: Mix cooked lentils with rice and vermicelli, add boiling water to cover.
Prepare Pasta: Boil spaghetti and marbled pasta in salted water, drain without rinsing.
Assemble Koshary: Layer pasta, rice, and lentils, then top with sauce, daqqa, and crispy onions.