Combine herbs, walnuts and breadcrumbs in the food processor and pulse until finely chopped and well mixed. Pour into a bowl and add olive oil to make a paste. Spray a baking dish with cooking spray and place the mahi mahi in the dish. Press breadcrumb mixture onto the top of each filet, then season with salt and pepper.
Cover with foil and bake at 375 degrees for 15 minutes. Remove foil and place under the broiler for 2-5 minutes to brown the topping, watching closely to be sure it doesn't burn.
Recipe by Cooking With MicheleĀ® at https://cookingwithmichele.com/2011/04/herb-and-walnut-crusted-mahi-mahi-2/