Run your pumpkin under water and scrub it to clean it.Cut it in 2, remove the seeds inside and cut it into small cubes.If you wish, you can peel it but it is not essential.
In a casserole dish, gently heat the olive oil with the pressed garlic and sage leaves for 1 to 2 minutes.
Pour in the water, stir and add the pumpkin cubes as well as a pinch of salt, turmeric and nutmeg.Cover and cook for around twenty minutes. The pumpkin should be very tender.
Scoop out the cooked flesh of the pumpkin and remove the water if any remains, but keep it to adjust the texture if necessary.Remove the sage leaves.Place the pumpkin in a blender and blend until the texture is uniform.Add the butter and stir well, then the cream. You can add a little cooking water if necessary to achieve the desired texture.