Peel the pumpkin with a vegetable peeler and cut into cubes. Cook half of the pumpkin cubes in a water and a pinch of salt until they are tender.
Dice the zucchini and chop the onion and garlic. Cut the tomato into cubes. Remove the thyme leaves from the sprigs and chop finely.
Cook the pasta according to the instructions on the package and preheat the oven to 200 ºC. Fry the onion, garlic and thyme with the remaining cubes of pumpkin and zucchini in a little olive oil. Put a lid on the pan and simmer for about 10 minutes.
Grate the lemon on top. Add the tomato paste and diced tomato. Fry for a while and season with salt and pepper.
Drain the cooked pumpkin. Blend finely with the mixer and toss in the pumpkin-zucchini mixture. Now add the cooked pasta. Add some pumpkin moist to make it more liquid if necessary.
Add some olive oil in a frying pan and cook the balls for a few minutes. Scoop the pasta mixture in an oven dish and divide the balls on top. Sprinkle some vegan cheese and leave to cook for about 5 minutes in the oven until the cheese has melted.