Heat one tablespoon (15 milliliters) of olive oil in a pan. Make crosshatches in the fish. Dredge it in flour, then tuck the rosemary and sage inside. Fry it in the pan until golden brown on both sides.
Add potatoes, garlic, and leek to a bowl. Add two tablespoons (30 milliliters) olive oil, salt, and pepper.
Toss to coat. Pour mixture into a baking dish. Place fish on top.
Pour wine around fish. Drizzle remaining olive oil on top. Cover with foil.