Mix flour and chilled butter (cut into pieces) in a mixer or with a fork- add sour cream and vinegar and combine well. Form into a ball of dough and refrigerate.
Cut the pumpkin into chunks and coat with oil, salt, and pepper. Roast on a baking tray in the oven for approximately 20 minutes at 375 degrees. Flip pieces once to twice during baking.
Combine tofu, garlic, lemon juice, pepper, nutmeg, and flour in a blender or food processor. Add one cup of cooked pumpkin and blend well.
Meanwhile, sauté the onion slices in oil over medium-low heat. When soft and starting to brown add in the vinegar and syrup and turn heat to low...cooking until soft and sweet.
Roll dough out on a floured surface or a piece of parchment paper. Pour filling into the middle of the dough and place cubed pumpkin, chunks of vegan cheese, and thyme over the filling. Sprinkle with onions and top with salt and pepper.
Fold the sides of the dough up around the filling to form an open-faced ‘galette’.
Bake at 400 degrees for 30 minutes or until brown. You may brush the crust with soy or nut milk to ‘glaze’ it if you wish.
Enjoy with a side salad for a delicious meal, or serve as an appetizer or first course at your net holiday gathering.