Place the olive oil in a medium skillet over medium-high heat.
Add the onion, carrots and garlic.
Reduce the heat to medium and cook until the onion has softened slightly. Stir frequently.
Add the mushrooms and cook for about 4 minutes. Stir frequently.
Add the vegetable stock, salt, pepper, tarragon, thyme, oregano and sage.
Reduce the heat to medium-low and cook for 30 minutes. Stir occasionally. If the liquid reduces below about 1/2 cup, add water 1/4 cup at a time.
While the sauce is simmering, line a 9 inch square Pyrex dish with foil.
Preheat the oven to 325°F.
Place a layer of lasagna noodles in the bottom of the Pyrex dish.
Place 1/3 of the thinly sliced zucchini on top of the lasagna noodles at a 90° angle.
Spread 1/3 of the vegetable sauce mixture over the top of the zucchini.
Add a layer of noodles and then place 1/3 of the thinly sliced zucchini on top of the lasagna noodles at a 90° angle.
Place half of the cheese slices on top of the zucchini.
Add a third layer of the lasagna noodles and top with the remaining vegetable mixture.
Place the remaining 1/3 of the thinly sliced zucchini on top of the lasagna noodles at a 90° angle.
Cover the Pyrex dish with foil and bake for 60 minutes.
Remove the foil from the top of the lasagna and place the remaining sliced cheese across the top of the lasagna.
Bake for about 5 minutes and serve.