1. Knead the ingredients for the crust in a machine or by hand: it can be rolled out immediately. Line a 30 cm diameter tart pan with the crust. Chill in the refrigerator. Preheat the oven to 190°C (375°F).
2. Clean the leeks, slice them, take 260 g, and blanch them two to three times in salted water. Set aside. Meanwhile, using a large knife.
3. Cut the pumpkin into about ten large pieces. To do this: start by making a vertical incision on the side, this "flat" side will serve as a support to lay your pumpkin flat on the work surface.
4. Scoop out the pieces with a tablespoon and finally, peel them with a peeler, it takes time but it's necessary, you should have about 500 g of pumpkin left for the recipe.
5. Place the pieces in a saucepan and cover them with salted water. Cook for about 15 minutes once it boils. When they are cooked, drain and let cool. Take half of the pieces, set aside the rest.
6. Blend the first 250 g of pumpkin with the 60 g of pesto (parmesan-free) and the silken tofu, season with salt, pepper to taste, and a pinch of sugar to enhance the flavor of the pumpkin.
7. Cut the other half of the pumpkin into cubes, add them to the previous mixture, along with the pre-cooked sliced leeks.
8. Spread the organic tomato sauce on the bottom of the tart crust using the back of a spoon, and lightly sprinkle with a final pinch of sugar.
9. Finally, spread the pumpkin mixture over the prepared tart crust.
10. Top with crushed and toasted hazelnuts, bake for about 25 to 30 minutes.
11. Serve with grated raw beetroot, green salad, and herb vinaigrette.