Preheat over to 450 degrees.
Combine pumpkin, onion, garlic and herbs on a rimmed baking sheet.
Drizzle with oil and season with salt and pepper.
Toss to coat pumpkin, then, (tossing vegetables halfway through) until pumpkin in slightly caramelized and very tender when pierced with tip of sharp knife.
Discard any woody stems from the herbs, leaving the leaves.
Transfer vegetables to a blender.
Add stock and cream.
Blend until smooth, adding more stock if necessary to achieve desired consistency.
Transfer to pumpkin enamel cast iron pot.
Bring to a slight simmer over medium heat.
Add cheese and whisk until smooth.
Season with salt and pepper.
Serve, garnished with heavy cream and roasted pumpkin seeds, if desired.