With the rack in the lowest position, preheat the oven to 200 °C (400 °F). Line a 17 x 12-inch (43 x 30 cm) baking sheet with parchment paper.
On a floured work surface, roll out the dough into a 10-inch (25 cm) square. Place the dough on the baking sheet. Spread the sour cream over the entire surface of the dough and top with the shallot.
Thinly slice the top of the squash with a mandolin. Set aside. Cut the bottom in half, remove the seeds and slice thinly. On the square of puff pastry, place the half slices, overlapping. Continue with the remaining slices so as to cover the entire surface. Brush with the butter. Season with salt and pepper.
Bake for about 30 minutes or until the dough is cooked and the squash is tender. Add the goat cheese and cook for an additional 3 to 5 minutes, until the cheese is warm. Cut into squares. Serve as a hors-d’oeuvre.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.