Place all vegetables and pear on baking sheet and drizzle with 3 Tbsp oil, and sprinkle with salt and pepper. Toss to coat, then bake at 425F for 45 minutes or until tender and golden brown (flip veggies half way through roasting).
Place everything into a food processor (or use an immersion blend in a large stock pot), and process until smooth. Add a bit of chicken stock if needed to make it easier to purée, then pour into a large stock pot.
Add remaining chicken stock and thyme and bring up to a boil and allow to simmer for 15 minutes. Adjust to taste with salt and pepper, then stir in walnut pesto and cream, if desired.