Preheat oven to 425°F (220°C). Line two baking sheets.
In a small bowl, combine garam masala, curry powder, coriander, turmeric, cumin, cayenne, and 2 tsp vegetable stock powder.
Toss cauliflower and sweet potato separately with 1 tablespoon olive oil and ½ tablespoon spice mix each, spread on baking sheets, drizzle with another ½ tablespoon olive oil, and roast - cauliflower for 25–30 minutes and sweet potato for 35–40 minutes, flipping halfway.
In a large pot, heat ½ tbsp olive oil over medium heat. Add onion and cook 2–3 minutes. Stir in garlic, ginger, chickpeas, bay leaves, and remaining spice mix. Cook 1 minute.
Add lentils, water, tomato paste, soy sauce, and 2 tsp vegetable stock powder. Bring to a boil, then reduce heat and simmer, covered, for 20 minutes, stirring occasionally.
Remove bay leaves. Stir in coconut milk and spinach until wilted. Gently fold in roasted vegetables. Off heat, stir in lime juice to taste. Adjust seasoning as needed.
Spoon over rice and top with coconut yogurt, lime wedges, and chili if using.