Get out 4 sheets of heavy duty aluminum foil that are 20-inches (50-cm) long and lay them on your work surface. Spray the non-shiny side of the foil with cooking spray or brush them with a little olive oil to keep the fish from sticking. If you're using regular foil, you may need to double the the foil so it's sturdy enough to contain the tilapia and vegetables. Get out 4 frozen fillets of tilapia and run them under cold water. Set them on a plate and use paper towels to pat them dry. If you're using thawed fish, you don't need to rinse and dry the fish. Lay 1 fillet of frozen tilapia in the center of 1 piece of foil. Repeat this for each fillet. Sprinkle the fish with salt and pepper according to your taste. Get out 2 tablespoons (28 g) of butter and slice them into thin pieces. Top each of the fillets with some of the butter and 2 slices of the lemon. Put 1 thinly sliced zucchini, 1 sliced bell pepper, 1 chopped tomato, and 1 tablespoon (8.5 g) of drained capers into a mixing bowl. Drizzle 1 tablespoon (15 ml) of olive oil over the vegetables and sprinkle 1 teaspoon (5.5 g) of  salt and 1/4 teaspoon (0.5 g) of black pepper over them. Stir the vegetables until they're combined. Substitute your favorite vegetables for any of these listed here. For example, use a summer squash instead of a zucchini or tomato. Scoop 1/4 cup (40 g) of the vegetable mixture on top of each fillet of fish. Fold both of the long sides of foil up towards the middle. Fold the sides together to seal the the foil in the center. Roll together the ends of the packet to seal it completely shut. Set each foil packet directly on the oven rack. Cook the packets for 30 minutes and remove them from the oven to check if the fish is cooked. Carefully open a packet to let the steam escape and drag a fork over the center of the fish fillet. If it's finished cooking, it should flake easily. If not, reseal the packet and return it to the oven to cook for 5 to 10 more minutes. Turn off the oven and remove all of the foil packets from the oven. If you want to serve the fish and vegetables directly from the packet, set 1 packet on each serving plate. Let your guests open their own foil packets. Transfer the leftover fish and vegetables to an airtight container. Store the leftovers for 3 to 4 days in the refrigerator.
سخني الفرن مسبقًا إلى حرارة 220 درجة مئوية وجهزي القصدير. اشطفي السمك البلطي المجمد وجففيه. رصي السمك على القصدير مع الزبدة وشرائح الليمون. اخلطي الخضروات المقطعة وزيت الزيتون والتوابل. غطي السمك بخليط الخضروات وأحكمي غلق أغلفة القصدير. اتركي لفائف القصدير في الفرن لمدة 30-40 دقيقة. أخرجي السمك البلطي والخضروات وقدميهم.