PREHEAT the oven to 200°C/400°F. HEAT the oil in a large frying pan over a medium heat and cook the onion for 8 minutes, stirring occasionally. ADD the garlic and cook for 2 minutes. ADD the red wine, tomatoes, tomato paste, rosemary, oregano, pepper and 1 teaspoon of salt and simmer, covered, for 5 minutes. ADD the mushrooms and lentils, return to a simmer, cover, and cook for 5 minutes, then remove from the heat. HEAT 1¾ cups of the milk plus the remaining ½ teaspoon of salt in a saucepan over a medium-high heat until almost boiling. WHILE the milk is heating mix together the remaining ¼ cup of milk with the cornstarch in a small bowl until well combined. STIR the cornstarch mixture into the hot milk in the saucepan and continue stirring until thickened. STIR in the grated cheeses until well combined. SPOON a little of the mushroom and lentil sauce into the bottom of a deep baking dish (approximately 11 x 7 inches) and top with lasagna sheets. SPOON over half of the remaining sauce, top with lasagna sheets, then top with half the cheese sauce. REPEAT the layers, finishing with a layer of cheese sauce on top. BAKE for 35 minutes, then remove from the oven and let stand for 10 minutes before serving.