Preheat oven to 425°

In a large mixing bowl, combine broccoli, mushrooms, zucchini and carrots.  Drizzle the vegetables with olive oil, and season with salt & pepper.  Spread vegetables in a single layer in a shallow baking dish.  Roast vegetables in preheated oven for 30 to 40 minutes; stir halfway through their cooking time.  When finished cooking, remove for the oven and reduce oven temperature to 350°.

In a large pot cook potatoes until done.  Drain, mash.  Measure out 4 cups. Add butter. Stir the mashed potatoes with a fork until they are smooth.  Stir in roasted vegetables.

In a dry, nonstick skillet over medium heat, quickly heat each tortilla on both sides to make pliable.  Dip the tortillas in enchilada sauce.  Put a large spoonful of potato-veggie mixture into the center of each tortilla.  Top mixture with 1 to 2 tablespoons cheese and roll tortillas.  Place seam side down in a 9x13 baking dish.  Pour extra sauce over top and sprinkle with remaining cheese.

Bake at 350° for approximately 20 to 30 minutes or until the enchiladas are heated through.