This spicy miso fish en papillote recipe is one of the best ways to cook fish without an odor. It’s incredibly fast and easy and works with most fish fillets. The vegetables need to... be cut very thin and small to cook quickly. It is traditional and healthiest to use parchment paper to make the packets, but I have used foil as it is easier to handle. You can line the foil packets with parchment paper if you like. The important thing is not to make them too small as the fish and veggies will create steam, which will expand in the packets.
Miso is used here as a marinade. Miso comes in different colors and strengths, the darker the miso, the stronger the taste. For fish, the sweeter, lighter, yellow colored “miso shiro” works best.
Blend the miso with 2 teaspoons of lime juice and rub paste all over the fish. Let marinate in the fridge for 30 minutes to an hour.
Preheat the oven to 400 degrees.
Tear off 2 squares of aluminum foil large enough to comfortably hold 1 fish fillet. If lining your packets with parchment paper, make it the same size as the foil, and lay it on top of the matte side of the foil.
Smear the center of each foil/parchment square with 1 teaspoon of sesame oil. On top of the oil, dividing evenly between the 4 squares, place shallots, ginger, garlic, tomatoes, jalepeño, cilantro, and scallions. Top the vegetables with a fish fillets, skin side up and add 1 teaspoon soy sauce.
Fold the foil in half over the fish and tightly roll the sides of the packet together to seal, leaving a small gap open. Mix the remaining lime juice and the water together and divide between each packet, pouring through the gap. Finish sealing them. The packet should have the look of a giant empanada.
Lay the packets on a cookie sheet and bake in the oven 10-15 minutes depending on the thickness of the fish. Carefully open the packets – there will be steam! You can either plate the fish and vegetables, or serve them in the ½ open packets. Sprinkle with sliced scallions.