Make the tomato sauce. Peel the onions and garlic. Finely chop the onions. Heat the olive oil in a pan. Add the onions, press the garlic over it, and let it sauté.
Add the tomato paste, thyme, bay leaf, rosemary, and chili flakes. Let it simmer for a while.
Add the vegetable broth and the peeled tomatoes. Bring to a boil and stir occasionally.
Season with balsamic syrup, pepper, and salt. Lower the heat and let it simmer for 10 minutes.
Preheat the oven to 200 °C.
Chop the Swiss chard into small pieces. Heat 2 tablespoons of olive oil in a pot and sauté the spinach and Swiss chard. If using frozen spinach, let it thaw. Season with pepper and salt.
Cut the mushrooms into quarters. Sauté them in olive oil. Season with pepper and salt.
Mix the ricotta with the Swiss chard and spinach. Season with pepper and salt.
Chop the basil and mint finely. Cut the mozzarella into pieces.
Spoon some tomato sauce into a baking dish.
Cover the bottom with lasagna sheets. Spread the ricotta mixture over it. Spoon the mushrooms into the baking dish and sprinkle the basil, mint, and mozzarella on top. Place lasagna sheets on top. Spoon some tomato sauce over it. Grate the parmesan and sprinkle it on top.
Place the baking dish in the oven for about 25 to 30 minutes until the lasagna is cooked and you have a crispy crust on top.
Tips
No extra tips needed, Just Enjoy!