Cut the top of the pumpkins, and scoop the seeds out. Put the pumpkins in the oven for about 25 min (more if they are big). When they are cooked, take them out of the oven and let them cool for a little bit. Then scoop out the flesh and put it in a bowl: it should come really easily if your pumpkin is well cooked and you should be left with only the skin.
In a large bowl, put the pumpkin purée, the coconut milk, eggs, sugar, cinnamon, ginger, nutmeg and salt. Mix well: it should result in a very wet batter. Pour into a prepared pie dish. Bake about 50 minutes.