
This miso mayo foil-baked salmon is a fast, flavorful dinner with tender fish, sweet onion, and earthy shimeji mushrooms. The foil keeps everything moist while the miso-mayonnaise topping turns rich and savory in minutes.
Preheat the grill or broiler to medium-high. Thinly slice the onion. Trim the base of the shimeji mushrooms and separate them into small clusters.

In a small bowl, mix the miso and mayonnaise until smooth and evenly combined.

Lay each salmon fillet on a sheet of aluminum foil. Spread the miso-mayonnaise mixture over the top of the salmon, then divide the onion and shimeji mushrooms among the fillets.

Fold and seal the foil packets tightly. Grill or broil for 10 to 15 minutes, or until the salmon flakes easily with a fork. If cooking in a skillet, add a small splash of water to the pan, cover, and steam-bake the packets over medium heat until the salmon is cooked through.

Carefully open the foil packets to release the steam. Serve the salmon hot with the softened onions, mushrooms, and any juices collected in the foil.

If shimeji mushrooms are unavailable, use shiitake or oyster mushrooms instead. Do not overcook the salmon; start checking at 10 minutes, especially if the fillets are thin. Leftovers can be refrigerated in an airtight container for up to 2 days.