Prepare the Filling: In a large pot, combine mushrooms, onion, garlic, carrots, potatoes, cauliflower, green beans, and peas. Add vegetable broth, salt, pepper, soy sauce, and water. Bring to a simmer and cook until vegetables are tender.
Mix cornstarch with a little water, then stir it into the pot to thicken the filling. Cook for an additional 5 minutes and set aside.
Make the Pie Crust: In a bowl, mix flour, salt, and sugar. Add cold plant-based butter and use a pastry cutter to work it into the flour until it resembles coarse crumbs.
Gradually add cold water, 1 tbsp at a time, and mix until dough forms. Divide the dough into portions for individual pot pies.
Assemble the Pot Pies: Grease Souper Cube 2-cup trays. Roll out the pie crust and cut pieces that will fit inside the trays. Press the crust into the trays.
Fill each crust with the veggie filling and top with more crust. Crimp the edges and make small slits on top for ventilation.
Bake: Preheat oven to 375°F. Place the pot pies on a baking sheet and bake for 30-35 minutes, or until the crust is golden and crispy.
Serve: Let cool slightly before serving. Enjoy your comforting, veggie-packed pot pies!