Peel and chop the garlic and onion. Cut the leek into rings. Peel the carrots and cut into small pieces, slice or halve the mushrooms depending on their size. Heat 2 tbsp. oil in a pan and sauté the garlic, onion and leek. Add the carrots, a little thyme and bay leaf and sauté briefly. Pour in the vegetable stock, season with salt and pepper and simmer for 8 minutes. Heat the remaining oil in a large pan and sear the mushrooms. Drain, rinse and drain the beans. Cook the farfalle in salted water according to the instructions until almost al dente. Add the mushrooms and beans to the stew and simmer for a further 8 minutes. Add the drained pasta and simmer for a further 3 minutes. Flavour with salt and pepper. Serve with the parmesan.