View the original recipe via:
PEEL and finely chop the onion. PAT the sole fillets dry using paper kitchen towels and season them with pepper and salt. HEAT a knob of butter along with a dash of olive oil in a large skillet.
COOK the fish a few minutes on both sides until they're beautiful golden brown. TRANSFER the fish to a plate and cover with tin foil.
HEAT the skillet again and add some more butter if needed and sauté the onion for a few minutes. ADD lemon juice and apple cider and bring to a boil. ADD lemon zest and mustard and let it reduce for a few minutes.
ADD crème fraîche and SEASON with pepper and salt. TRANSFER the sole fillets back into the sauce and heat it for a few minutes. SERVE with pasta and a salad, enjoy!