Fish filets with potatoes and spinach

This came to me as last minute inspiration. I had frozen red snapper filets, frozen spinach and soy cream and we had to eat :-) - 3 to 4 big potatoes - 5 to 6 cups frozen spinach (or even better, equivalent in fresh) - 1 big onion - 2 to 3 cloves garlic - Enough broth to cover potatoes while cooking - Breadcrumbs -