Warm olive oil in a heavy pot over medium heat. Add onion, garlic, and celery; sauté until translucent and lightly golden, 8–10 minutes, stirring often.
Stir in carrots and pumpkin purée. Pour in broth; add thyme, bay leaf, and a pinch of salt and pepper. Bring just to a boil, then reduce to a gentle simmer. Cover and cook 25–30 minutes until vegetables are tender.
Remove bay leaf. Stir in cooked barley or rice; simmer 5 minutes to warm through. Taste and adjust salt and pepper; add a squeeze of lemon if desired.
Ladle into bowls and serve hot. Optional: swirl of olive oil, fresh herbs, or a spoon of yogurt.
