Wash the sweet pumpkin thoroughly, remove the seeds, and steam it.
Scoop out the flesh of the pumpkin and mash it finely.
Add sugar, heavy cream, egg yolk, and salt to the mashed pumpkin and mix well.
Combine flour, butter, and salt to make the tart dough.
Spread the dough evenly into the tart pan and poke holes in it with a fork.
Pre-bake the dough for 10 minutes in an oven preheated to 180°C.
Pour the sweet pumpkin filling onto the baked tart shell and smooth the surface.
Bake in the oven at 180°C for 20 minutes.
Let it cool, remove from the pan, and serve.