Heat oil in a large stock pot over moderate heat. Add onion, garlic, carrots, celery and bell pepper and stir. Season with salt and pepper and stir until the veggies start to soften.

Add squash, chicken broth, water, bay leaf, and thyme and bring to a boil. Add soup base and lentils and reduce heat.

Simmer for 20 minutes, add mushrooms, and continue simmering until the squash is fork tender. Taste for seasoning and adjust if necessary.

Serve warm, preferably with some nice, crusty bread for soaking up all of the goodness.