Preheat air fryer at 160°C for 3 minutes.
Combine walnuts with egg white in a small bowl.
Set aside.
In a separate small bowl, combine cumin, cayenne pepper, cinnamon and erythritol.
Add walnuts, drained of excess egg white, and toss.
Place walnuts in ungreased air fryer basket.
Cook for 6 minutes, then toss nuts and cook for an additional 6 minutes.
Transfer to a small bowl and let cool for about 5 minutes until easy to handle.
When cooled, chop into smaller bits.
Adjust air fryer temperature to 200°C.
Place Brie in an ungreased pizza pan or on a piece of baking paper cut to size of air fryer basket.
Cook for 10 minutes.
Transfer Brie to a medium serving plate and garnish with orange marmalade and spiced walnuts.