Sauté the onions in the butter or oil until translucent. Add the chopped spinach and the dill and cook covered until the spinach is wilted. Remove from the heat, add the almonds and lemon juice, and allow to cool. Rinse the flounder. Place each fillet, skinned side up, flat on a board. Spoon a small amount of the spinach filling onto each fillet and then roll it up. Place the rolled fish in an oiled baking pan and bake covered at 375° for 20-25 minutes, until the fish is tender and flaky. Flounder Florentine is delicious served with Artichoke Heart and Tomato Salad.
Thanks to Angela Ross and Moosewood Restaurant.