Sprinkle both sides of fillets with salt. Place parchment paper square on work surface and coat with butter. Place one fillet in the center of the square. Sprinkle fish with lemon juice. Place 2 pats butter on fish, 1 bay leaf, 1 teaspoon thyme, and 1 sprig parsley. Scatter with scallions and a tomato slices. Repeat with all fillets. Fold paper around as if making a package. Put a toothpick through the folds of the paper to hold it together. Sprinkle packages with water and place them on a cookie sheet and bake in 450 degree oven for 20 minutes.