In a small frying pan, brown pepitas over medium heat until they are browned. You will start to smell them and hear them popping when they're done. Set aside for garnishing the bisque later.
In a large saucepan or Dutch oven, melt butter over low to medium heat.
Add chopped onion to the pan.
Sauté onions in butter until translucent.
Add pumpkin purée, vegetable broth, salt, pepper, garlic powder, nutmeg, ginger, cinnamon, cayenne pepper and brown sugar.
Stir until combined. Bring the bisque to a boil over medium heat and then turn down to just a simmer. Simmer bisque for 10-15 minutes, stirring often. Remove from heat.
Using your emulsion blender on low speed, blend the bisque until puréed, thick and creamy. (If using a regular blender, blend half of the bisque at a time on purée setting and then return to the saucepan.
Move your saucepan back to the burner on low and add the heavy whipping cream.
Stir in cream until completely combined. Leave on burner until hot but do not boil.
Remove bisque from heat.
Divide bisque between four soup bowls and garnish with toasted pepitas, nutmeg and a little bit of the cream. Enjoy!