Parchment-Baked Mackerel with Mushrooms and Tomatoes

Fillet the mackerel, then season with salt and pepper.

Slice the onion and finely chop the garlic.

Peel the tomatoes and dice them.

Slice the mushrooms.

Sauté the onion in a pan, add the mushrooms, and then toss in the tomatoes, salt, pepper, and sugar.

After a minute, stir in the parsley and garlic.

Cook for one more minute, then remove from the heat.

Cut out 2 rectangular sheets of foil and parchment paper.

Place the filling on the parchment, top with the fillets skin-side up.

Wrap securely in the parchment, then wrap in the foil. Repeat for the second portion.

Bake at 180 °C (350 °F) for 15–17 minutes.