Heat a frying pan and drizzle in the olive oil.
Chop the onion and garlic as finely as possible and add it to the pan along with the roughly chopped mushrooms.
Add the vegetable cube, thyme, and grated carrot. Stir and cover with a lid just long enough to soften the mushrooms.
Cook for 5-6 minutes over medium heat until the vegetables have browned.
Now make the béchamel sauce in the vegetable pan. Sprinkle the flour over the vegetables, using a sieve to avoid lumps, and stir quickly.
Add the butter and milk. Stir until smooth.
Season with salt and pepper, and simmer until the sauce begins to reduce.
When the sauce is reduced and has a creamy consistency, remove from the heat, and sprinkle with the fresh greens and parmesan cheese.
Enjoy with a squeeze of lemon and fresh toast.