Cut off the ridge of the clod with scissors. Cut off the caudal fin and head with a larger knife. Cut the clod along the back strand and use the knife to remove the fillets close to the bones.
Flour the fillets on both sides and fry them on the skin side in a pan with oil. In the meantime, fry the onions and bacon in a second pan.
Turn the plaice fillets after approx. 2 - 3 minutes. When the bacon is crispy and the onions translucent, add a piece of butter. Add another piece of butter to the fish and drizzle the melted butter over the fillets. Turn off the stove. Chop the parsley and add to the bacon stick. Spread the bacon stick on the plaice and serve.