1. Preheat Oven:
Preheat your oven to 425°F (220°C) and prepare a large baking sheet.

2. Make Spice Blend:
In a small bowl, combine the turmeric, cumin, chilies, coriander, cinnamon, fenugreek, and fennel seeds. Set aside.

3. Roast Cauliflower:
Place the cauliflower florets on the baking sheet. Drizzle with 2 tablespoons of olive oil, half of the spice blend, and season with salt and pepper. Toss to coat and arrange in a single layer. Roast for 40 minutes, flipping halfway through, until deeply caramelized.

4. Prepare Sauce:
While the cauliflower roasts, heat the remaining 2 tablespoons of olive oil in a large skillet or braiser over medium heat. Add the diced shallots and sauté until soft and translucent, about 5-6 minutes.

5. Add Aromatics and Lentils:
Add the remaining spice blend, ginger, and garlic to the skillet. Sauté for 1 minute until fragrant, then stir in the split red lentils.

6. Add Liquids:
Stir in the crushed tomatoes, coconut milk, and vegetable stock. Bring the mixture to a boil, then reduce to a simmer for 25 minutes, stirring often, until the lentils are soft. Add more stock as needed if the mixture becomes too thick.

7. Season and Blend (Optional):
Once the lentils are cooked, season with salt, pepper, and lime juice. For a smooth sauce, blend until silky in a blender, or leave it chunky if preferred.

8. Combine and Serve:
Add the roasted cauliflower to the sauce and stir to combine. Bring to a light boil over medium heat, then remove from heat.

9. Garnish:
Serve with chopped cilantro, nigella seeds, lime zest, and extra lime juice.