In a large heavy bottomed skillet, saute the onion in a splash of olive oil until translucent. Add mushrooms and garlic. Saute until the mushrooms release their liquid, about 8 minutes.
Add zucchini to skillet, and cook another 5 minutes. Mix in carrots, spinach, balsamic, salt and pepper and stir until the spinach is wilted. Remove from heat.
Cheese Filling
In a medium bowl, combine all ingredients for the cheese layer.
Lasagna
Cook noodles according to package directions.
Spoon about a ½ cup sauce into the bottom of a 9x9 inch glass baking dish.
Place 3 noodles over the sauce so that they are overlapping. Spread half of the cheese filling on top of the noodles, top with half of the veggie filling, and top veggies with a ½ cup marinara sauce.
Repeat step 3 one more time.
Top lasagna with the final 3 noodles, remaining sauce, and provolone slices.
Cover the lasagna with foil and bake at 400 F for 25 minutes. Remove the foil and bake 15 more minutes, or until the cheese is starting to brown. Let cool some before serving.
Notes
Lay cooked lasagna noodles out on parchment paper so they are not touching while you are layering the lasagna.
Recipe by Alison's Allspice at https://www.alisonsallspice.com/small-batch-veggie-lasagna/