Pre-heat oven to 425 F = 220 C.
Butter a baking dish.
Place fish in the dish, skin side down.
Mix lemon juice with salt and pepper.
Brush fish with the lemon mixture.
Brush with olive oil.
Sprinkle dry mint then transfer the dish to the fridge for 4 hours (you can skip this step if the smell of fish doesn't bother you as much)
Remove dish from the fridge and pour the remaining oil over the fish.
Add lemon zest.
Pour the remaining lemon juice over the fish.
Place the sliced lemon over the fish.
Add fresh thyme.
Bake in the middle of the oven for about 15 minutes.
Remove from the oven and sprinkle fresh parsley then serve.