When its boiled we reduce the heat in medium fire and and we leave it to cook until the pumpkin is soft, (around 20 minutes). When is ready we filter and we keep in a bowl aside all of the boiled water we had in our pot and with a minipimer we squash the mix of potatoes, pumpkin and onion till we have a nice creamy result. If it's too thick we add some of the boiled water we kept aside.