DIRECTIONS
Preheat oven to 400 degrees.
In a small bowl, mix the butter and tarragon or basil until combined; set aside.
Lay out 4 large pieces of foil. Layer the vegetables in the center of each piece, starting with the mushrooms, then the celery and scallions.
Dot the vegetables with half of the herb butter and season each portion with ¼ tsp. salt and pepper to taste.
Lay the flounder fillets over the vegetables; dot with the remaining herb butter.
Sprinkle each fillet with ¼ tsp. salt and pepper to taste.
Bring the foil ends together, fold over and crimp closed on all sides to make sealed packets.
Place the packets on a baking sheet and bake until the fish is cooked through, but still moist, 18 to 22 minutes.
Remove packets from oven and let sit for 2 minutes before opening.
Serve with the cooking juices.
Serves 4.