1⁄3 finely chop the cashew kernels and mix with the crumbs. Coarsely chop the remaining kernels. Wash fillets, dab dry, season with salt and pepper. Whisk the egg. Turn fillets in flour, egg and crumb mix.
Heat 2 tablespoons of oil in a frying pan. Fry the fillets on each side for about 6 minutes at medium heat. Fry the remaining seeds for about 3 minutes.
Wash the spinach and drain. Wash the tomatoes. Peel and chop the onion. Heat 1 tablespoon of oil. Steam tomatoes and onion for about 3 minutes. Add the spinach and let it collapse. Season to taste with salt, pepper and nutmeg. Arrange everything.