1. Heat one tablespoon oil in a large saucepan and sauté garlic and spinach until soft and fragrant. Remove from pan and set aside.
2. Heat another teaspoon of oil and add portabella mushrooms and peppers (you may need to do in shifts) and cook over high heat until just softening – about four minutes.
3. Make a sandwich, layering the portabella mushrooms, the softened red peppers slices and feta cheese and spinach mixture between two slices of multigrain bread.