1. Heat oil in non-stick fry pan, add onion and cook until brown. Add asparagus and cook for a few minutes to soften, then add cherry tomatoes and stir to combine.
2. In a bowl, beat eggs and cream. Pour egg mixture over vegetables and cook on medium heat for 5 minutes.
3. Sprinkle with grated cheese and finish cooking under a preheated grill for 3 minutes or until the frittata is set.
4. Slide frittata out of pan onto your serving plate. To serve, add mixed salad leaves and drizzle over flaxseed oil and apple cider vinegar.