Preheat the oven to 425°F (220°C) and prepare a large baking sheet.

Make the spice blend: In a small bowl, mix together the turmeric, cumin, chili, coriander, cinnamon, fenugreek, and fennel seeds. Set aside.

Roast the cauliflower: Place the cauliflower florets on the baking sheet. Drizzle with 2 tablespoons of olive oil and sprinkle half of the spice blend, along with some salt and pepper. Toss well to evenly coat the florets. Arrange them in a single layer and roast for about 40 minutes, flipping the florets halfway through, until deeply caramelized.

Prepare the coconut tomato sauce: While the cauliflower is roasting, heat the remaining 2 tablespoons of olive oil in a large skillet or braiser over medium heat. Add the diced shallot and sauté for 5-6 minutes, or until soft and translucent.

Add aromatics and lentils: Stir in the remaining spice blend, ginger, and garlic. Cook for about 1 minute, stirring constantly, until fragrant. Add the red lentils and stir well to coat.

Simmer the sauce: Pour in the crushed tomatoes, coconut milk, and vegetable stock. Stir everything together and bring the mixture to a boil. Lower the heat and simmer for about 25 minutes, stirring often, until the lentils are soft and starting to break down. If the lentils absorb too much liquid, add more vegetable stock (or coconut milk for extra richness).

Blend the sauce (optional): Once the lentils are cooked, season the sauce generously with salt, pepper, and lime juice. For a silky smooth texture, transfer the sauce to a blender and blend for 1 minute, or leave it chunky if preferred.

Combine and finish: Once the cauliflower is roasted, add it to the skillet with the sauce. Stir gently to combine and heat everything through over medium heat.

Serve and garnish: Serve hot, garnished with chopped cilantro, a sprinkle of nigella seeds, lime zest, and a squeeze of extra lime juice.