Heat oil in a large pot. Add onions and cook over low heat until onions begin to turn a golden brown, approximately 25 minutes. Add crushed red pepper, pinch salt, collard greens and stock. Cover and reduce to low heat, stirring regularly. Cook until collard greens soften and reduce in size, about 30 minutes. Season with salt to taste.
In a small pan over low heat add sesame seeds, cumin, sunflower and pumpkin seeds and toast until seeds are lightly browned and fragrant. Serve greens garnished with toasted seed mix.
Recipe by Jonathan Dille, Executive Chef, The Grange, Providence