Cook the lentils in water for 20 minutes until tender. Drain. Cook the onion and ginger in the vegan butter until brown. Add the potato and tomatoes and cook for 5 minutes, then add the spices and coconut milk and cook for another 4 minutes. Add the lentils with the water, dill, honey and pepper and bring to a boil. Simmer until the lentils and potatoes are beginning to break up. Add the tamarind and cabbage. Cook until softened. Serve with chopped mint.