1. Prepare couscous following package directions, using vegetable broth in place of the water. Keep warm.
2. Season the fish with 1/4 teaspoon of the salt and 1/8 teaspoon of the black pepper. Coat both sides of fish in the flour, shaking off excess.
3. Heat a 12-inch nonstick saute pan or skillet briefly over medium-high heat; add 1 tablespoon of the oil and 1 tablespoon of the butter. When it sizzles, add two of the flounder fillets and saute for 2 minutes per side. Remove to a plate and keep warm. Add an additional tablespoon of oil and butter. Add the remaining flounder fillets and saute. Remove to the plate.
4. Add the shrimp and garlic and saute for 2 minutes. Stir after 1 minute so garlic does not burn and shrimp are evenly cooked. Add parsley, capers, lemon juice and remaining 2 tablespoons each oil and butter. Heat for 1 minute. Stir in the remaining 1/4 teaspoon salt and 1/8 teaspoon pepper.
5. To serve, place couscous on a large serving platter or divide among individual plates. Arrange the flounder over the couscous. Spoon shrimp and caper mixture over the top including all accumulated liquid. Garnish with additional parsley and lemon slices. Makes 4 servings.