Cook lasagna according to package directions. Drain and place on an oiled baking sheet until ready to assemble the pasta.
Prepare the vegetables
Sauté the onion and garlic in 1 tbsp oil until soft.
Add the mushrooms and thyme leaves. Sauté the mushrooms until they are cooked and have released their moisture. Salt and pepper to taste. Drain the mixture and place in a medium bowl.
Using the same pan, add a little oil to the pan if needed and sauté the zucchini until browned. Salt and pepper to taste. Add to the reserved vegetables.
Rinse the spinach and shake dry. Sauté the spinach in the same pan until wilted. Salt and pepper to taste and add the spinach to the rest of the vegetable. Mix all of the cooked vegetables together well and season if needed.
Make the cheese sauce
In a bowl stir together the herbed cheese and the ricotta until smooth
Assemble the pasta
Grease or oil a 9 x 12 baking dish. Place three strips of lasagna on the bottom of the pan. Spread about ¼ of the vegetables over the pasta then spread with a layer of cheese sauce. Sprinkle with ¼ cup mozzarella.
Repeat three times alternating the direction of the pasta for each layer.
Finish with a layer of pasta, topped with cheese sauce and sprinkle with the remainder of the mozzarella.
Preheat the oven to 425 degrees. Cover the lasagna with a piece of lightly oiled foil. Cook in the center of the oven for 30 minutes. Uncover and cook for a further 10 minutes until browned and bubbling. Remove from the oven and let cool for 10 minutes to allow the lasagna to set before cutting.
Recipe Notes
Lasagna can be refrigerated overnight before cooking. You may need to add 5-10 minutes to the cooking time if this is the case.