Small knob of butter (or double up the oil if you want to keep it vegan), coconut oil, heaped tsp cinnamon, heaped tsp garam masala, level tsp nigella seeds, garlic cloves, finely chopped, sundried tomatoes (can use plum or cherry if not available), chopped, heaped tablespoon tomato puree, leek - finely chopped, cube fresh ginger, grated, medium white potatoes, peeled and finely chopped, medium sweet potato, peeled and finely chopped