First do curry paste crushing in a robot or mincer, or by hand and mortar, half peeled onion, peeled garlic, peeled ginger, washed and dried coriander, chilli without seeds (omit if you do not like spicy, or use less), turmeric, cumin and coriander seeds, with the melted coconut oil.
Heat this paste, more or less homogeneous, in a saucepan or pot with a little more coconut oil until it melts and start to bubble, a minute or two. Add the banana and sauté the whole with a splash of coconut milk, mashing the fruit with the ladle.
Add the rest of the finely chopped onion, stir for a couple of minutes. Add the aubergine and pumpkin, add a little salt and stir well to incorporate the flavors. Lower the heat to medium power and sauté the whole for about 8-10 minutes.
Add most of the broth or water (if using water, add a little more salt) and the remaining coconut milk. Stir, bring to a boil, lower the heat and cover. Cook about 30 minutes, Stirring occasionally. Correct the liquid level if necessary and add to the point of salt.