Mix all vinaigrette ingredients in a bowl. Rinse the lettuce and sorrel leaves and pat dry. Remove tough stalks from the sorrel leaves. Tear the lettuce and mix with the sorrel. Arrange on a plate and drizzle with the balsamic raspberry vinaigrette.
Rinse the fish, pat dry and cut into about 7 cm pieces. Sprinkle with salt and pepper. Roll into rolls, placing a fresh rosemary leaf in the center of each (optional) and secure with a toothpick (for thicker fillets, first cut into thinner slices). Roll in flour, then dip in egg, and finally in Parmesan mixed with breadcrumbs.
Fry on a medium-hot pan, in oil and butter, browning the fish evenly on each side. Place the rolls on a baking sheet and put in an oven preheated to 180 degrees for 5-7 minutes, until the fish is no longer raw inside.
Serve with sorrel salad and balsamic raspberry vinaigrette (the salad can also be served in a separate bowl so the breading doesn't get soggy).