1 pound halibut fillet, cut into 1 1/4-inch cubes
1/4 teaspoon fine sea salt, more to taste
1/4 teaspoon freshly ground black pepper, more to taste
4 tablespoons extra virgin olive oil
1 small rosemary sprig
1/2 teaspoon dried mint
2 garlic cloves, minced
Fresh lemon juice, to taste (optional)
Chopped fresh mint, for garnish
Season halibut all over with a generous pinch of salt and pepper. In a mediumsize skillet just large enough to hold fish cubes in a single layer, heat oil over low heat. Add fish, rosemary sprig and dried mint, and let cook slowly until fish begins to turn opaque, about 3 minutes.
Stir in garlic and 1/4 teaspoon each of salt and pepper, and cook until garlic is fragrant and fish is just cooked through, another 3 minutes or so (heat should be low enough so as not to brown the garlic or fish but high enough to gently cook everything; the cooking time will vary widely with your stove).
Taste and add more salt and pepper and a few drops of lemon juice if desired. Stir in the fresh mint and serve, using a slotted spoon if you want to leave the poaching oil in pan; it is delicious over couscous or potatoes.