Step 1
Preheat the oven to 400 degrees F (200 degrees C).
Step 2
Split the pumpkin in half spoon out the seeds and place the pumpkin halves face down on a baking sheet. Split the potatoes lengthwise and place on the pan with the pumpkin. Bake the pumpkin and potatoes for 1 hour. Remove them from the oven and let them cool. When the pumpkin has cooled spoon out the flesh and put it into a large bowl. Cut the potato into 1/2 inch cubes.
Step 3
To make the dough in a food processor fitted with a steel blade put the flour and salt into the processor. Add the butter. Run the machine in spurts until the butter is in bits no bigger than pea-size. Add 4 tablespoons ice water and run the machine in spurts again just enough to bring the dough together. Turn the dough onto a work surface and knead it with your hands until the dough is soft and smooth handling the dough as little as possible. Form it into a flattened ball. Chill the dough for at least 30 minutes.
Step 4
Preheat the oven to 375 degrees F (190 degrees C). On a floured surface roll out the dough and use it to line the bottom and sides of either a 9 inch square baking pan or a large deep dish pie pan. Pierce the dough with a fork in three places. Line the sides of the pan with aluminum foil and crimp the foil gently to hold the dough in place.
Step 5
Bake the crust for 15 minutes. Remove the pan from the oven. Reduce the heat to 350 degrees F (175 degrees C). While the crust bakes make the filling.
Step 6
Heat the oil in a large skillet over medium heat. Add the onions and cook them stirring frequently until they soften about 5 minutes. Add the garlic and cook for 3 to 4 minutes more stirring frequently. Add the corn and cook for 2 more minutes. Remove the skillet from the heat.
Step 7
Stir in the pumpkin potato cheese thyme allspice salt and pepper. Mix well then spoon into pre-baked pie shell.
Step 8
Bake the pie at 350 degrees F (175 degrees C) for 30 minutes or until veggies and cheese are piping hot. Serve immediately.