1. Mix the salt, pepper and flour; cover the fish and remove the excess.
2. Heat the olive oil in a skillet over medium heat, brown the fish until cooked (about three or four minutes per side).
3. Remove the excess oil on absorbent paper.
4. Pour the white wine in the same pan where you cooked the fish and let it boil, stirring what was stuck to the bottom of the pan.
5. Add the lemon juice and capers, let the liquid reduce by half, add the butter in pieces, reduce the heat and mix quickly - this will make the sauce thicken.
6. Pour over fish and garnish with lemon slices.