Add oil to pan, heat on medium high.
Swirl to coat pot.
Add onion and garlic, sautee, stirring occasionally to prevent burning, until soft and lightly browned, about 6 minutes.
As onions cook, peel skin from sweet potatoes, and dice into 2" chunks.
Add stock to pan with onions and bring to a boil.
Boil potatoes until soft.
Do not drain.
Stir in cumin and red pepper, turn off heat.
Slowly add in cream and cheese, mixing well.
Return heat to medium high.
Using an immersion blender, blend soup until thick and creamy.
Stir in salt.
Divide soup evenly among 6 bowls; sprinkle roasted hazelnuts evenly over top.
Garnish with parsley or fresh diced sage if desired.