Wash the zucchini and cut off the ends. Cut the zucchini lengthways and cut into slices.
Heat the ghee in the pan. Simmer the onions, garlic, ginger and the curry paste over a medium heat for 15-20 minutes, stirring occasionally.
Fold in the tomatoes, broth and zucchini. Season to taste with salt and pepper and simmer for about 15 minutes until the zucchini are cooked through. Sprinkle with garam masala and stir.