PREHEAT the oven to 350F. Grease an 8” springform pan and set aside.
WHISK together the oil, vinegar and water, then whisk in the pizza crust mix.
TURN the pizza crust dough out into the prepared springform pan and use the heel of your hand and your fingertips to press it into an even layer across the bottom of the pan, then about halfway up the sides of the pan.
BAKE the crust for 10 minutes, or until it starts to firm up.
REMOVE it from the oven when the crust is done baking, and keep the oven heated to 350F.
ADD the toppings to the pre-baked crust: First, make an even layer of cheese out of 4-5 slices. Then add the butternut squash slices in an even layer. Top it with another layer of cheese slices. Then add the spinach and mushrooms. Top with the final layer of cheese. Finally, pour the sauce over the top and spread it into an even layer, making sure it is covering all of the cheese. Sprinkle 2-3 tablespoons Parmesan cheese over the sauce, if using.
BAKE for 40-50 minutes until the edges are golden and the sauce no longer appears shiny. Sprinkle an additional tablespoon or two of parmesan cheese over the top, if desired.
ALLOW to cool for about 5 minutes before removing the sides of the pan, slicing and serving.