Cut the pumpkin in half and scoop out the seeds with a spoon. Dice the flesh into 2 cm cubes.
Cook the pumpkin cubes in 100 ml of water for about 10 minutes (they're ready when you can easily pierce them with a fork). Drain and blend into a smooth purée. Let it cool.
Preheat the oven to 180°C.
Roll out the pastry and place it in a greased and floured tart tin (or use baking paper).
Prick the base with a fork.
Blind bake the crust for 20 minutes.
In a bowl, beat the eggs and add the brown sugar. Mix well until the sugar is dissolved.
Add the pumpkin purée and cream, and whisk until light and fluffy.
Stir in the butter, then add the spices. Use a mixer to make a smooth filling.
Crumble the speculoos cookies over the pastry base.
Pour in the filling and place in the oven.
Bake for about 30 minutes.
Serve with whipped cream.