Melt the butter in a saucepan. Mix the spices in a small bowl. Sauté the garlic and onion for 2-3 minutes while stirring. Sprinkle in the spices and steam for another 30 seconds.
Add tomatoes, lentils, lemon juice, vegetable stock and coconut milk to the saucepan and bring to the boil. Reduce the heat, simmer for 25-30 minutes, until the lentils are soft. If the lentils are too dry, a little more water can be added. Season to taste with salt and pepper and fill into plates. Garnish with coriander and lemon wedges and serve.