Cut the pumpkin into small cubes. Peel and dice the onion. Peel and dice the carrots as well.
Sauté the pumpkin, onion, and carrots in a little oil for a few minutes.
Add the vegetable bouillon, as well as the cream, bay leaf, and thyme. Cook the vegetables until tender (remove bay leaf and thyme) and blend the soup.
Season the soup with lemon, salt, and pepper. Optionally, garnish with pan-toasted pumpkin seeds sprinkled with a little salt, a dollop of crème fraîche, and some fresh thyme on top.