Rinse the fish and cut it into 4 pieces. Remove any bones, put it in a non-reactive dish, and refrigerate.
Wash the potatoes really well. Twist as you wash, some of the skin may come off.
Pluck 1 tbsp. leaves from the rosemary.
Wash and pat dry the parsley, pluck 1 cup leaves.
Measure out 1 tbsp. oregano.
Squeeze1/4 cup juice from the lemons through your fingers.
Peel 3 cloves garlic.
Start Cooking
Put the potatoes in a saucepan and cover them by about 1-1/2 inches with water. Add 1 tbsp. salt to the pot and put it over medium-high heat for about 12 minutes.
Pour the lemon juice in a bowl. Slowly whisk in 1/4 cup olive oil.
Crush the oregano in your fingers as you add it to the lemon juice and oil. Whisk.
Mince together the parsley and 2 cloves garlic, and whisk into the lemon juice and oil.
Pour half the sauce you just made over the fish. Turn the fish and refrigerate.
Check the potatoes – you want them still slightly crisp in the very center. If they are, drain them.
Put 1-1/2 tsps. of the vinegar in a medium bowl. Whisk in a pinch each of salt and pepper.
Slowly whisk in 3 tbsps. olive oil.
Mince that last clove of garlic and whisk it into the oil and vinegar.
Slice the potatoes into thick slices and add them to the vinegar and oil. Very gently toss, toss, toss. Set aside and forget for now.
Take the fish from the marinade and put it on a foil-lined baking pan. Put it under the broiler.
Broil the fish for 4 minutes. Drizzle the fish with some of the marinade you’ve used, then carefully turn it.
While the fish is broiling, mince the tablespoon of rosemary and add it to the potato salad, along with the olives. Gently toss.
