1. In a deep-frying pan, sauté onions in oil until golden.
2. Add peppers and continue sautéing on medium heat with partially covered pan, until soft.
3. Salt peppers lightly.
4. Meanwhile place fish in a dish and sprinkle with lemon juice and salt.
5. In a small bowl, combine honey and mustard.
6. Preheat oven to 400 f (200 c).
7. Transfer onions and peppers to baking pan, place fish slices on too.
8. Glaze fish with honey and mustard.
9. Bake uncovered for 25 minutes.