Moroccan Chickpea and Squash Stew

Name: Moroccan Chickpea and Squash Stew
Ingredients: 2 medium yellow onions; 2 tablespoons sunflower or vegetable oil; 2 medium stalks celery; 4 cloves garlic; 1 1/2 teaspoons ground cumin; 1 1/2 teaspoons ground coriander; 1 teaspoon smoked paprika; 1/2 teaspoon ground cinnamon; 1/2 teaspoon ground ginger; 3/4 cup dried split red lentils; 1/4 teaspoon crumbled saffron strands; 1 pinch granulated sugar; 12 ounces butternut squash; 8 dried apricots; 1 (15-ounce) can chickpeas; 1 (15-ounce) can or 1/2 (28-ounce) can whole tomatoes; 2 1/2 to 3 cups low-sodium chicken or vegetable broth; 1/4 cup uncooked white rice; 3/4 teaspoon kosher salt, plus more as needed; 1/2 teaspoon freshly ground black pepper; 1/4 medium bunch fresh cilantro; 3 tablespoons olive oil; Lemon juice; Aleppo pepper or other red pepper flakes, for serving (optional)