Dice the pumpkin and smother until ready.
Separately, boil the rice and rinse it with cold water.
Prepare the creme caramel by beating the eggs and mixing them with the milk, sugar and vanilla.
Put 1/2 the butter in a tray and wait for it to melt.
Pour on the creme caramel on top, add the rest of the butter which you've diced finely.
Put the tray in the oven and bake until ready.
After taking the tray out, sprinkle with crumbled walnuts and put in the fridge to harden well.