CRUST: In a medium-sized bowl, whisk together flours, salt, thyme, oregano, pepper and sugar. Pour into a food processor. Add in butter and olive oil. Pulse until the flour is crumbly. Add in water and pulse until the dough pulls away from the sides of the food processor. Turn dough out onto a floured sheet and knead it into a ball. Wrap in plastic wrap and refrigerate. Note: This can be done up to five days in advance. This also makes more crust than absolutely necessary.
SAUCE: In a medium-sized sauce pan on medium heat, melt the buttery spread. Add in the onion and cook, stirring occasionally until onion is translucent.
Add in the flour and stir continuously for one minute. Slowly pour in the vegetable broth, whisking continuously. Add in evaporated milk, white wine, thyme and rosemary. Stir and reduce head to medium-low. Allow mixture to simmer for 7-10 minutes, stirring occasionally. Season with salt and pepper.
FILLING: Toss the butternut squash with enough olive oil to lightly coat. Season with salt and pepper. Spread on a greased baking sheet and roast in a 400 degree oven for 40 minutes, stirring halfway through.
In a large bowl, mix the roasted butternut squash with the steamed vegetables. Stir in the prepared sauce. Pour the mixture into a large casserole dish.
On a floured surface, roll half of the crust out so that it is large enough to extend slightly over the edges of the casserole dish. Carefully place dough over the casserole dish. Crimp edges down with a fork. Slit a hole in the middle of the dish, so that steam is able to escape.
Bake in a 375 degree oven for 18-20 minutes, until crust is lightly browned.