If using, dice the bacon in small cubes. Wash the brown shrimp and dry on a paper towel.
Peel the onion and cube finely. Wash the parsley, and chop finely.
Wash the plaice fillets and pat dry with a pepper towel. Spoon lemon juice over them and season with salt and pepper.
Pour the flour onto a shallow plate. Toss the plaice fillets in the flour until they are covered.
Heat a frying pan and fry the bacon until crispy. Then remove from the pan and set aside.
Add 1 tbsp of butter and 1 tbsp of vegetable oil to the frying pan. On a medium heat, fry the plaice for 3-4 minutes on each side. Remove from the pan and keep warm.
Add the brown shrmip, onion bacon and parsley to the pan and warm slightly.
Add 3 tbsp of butter to the shrimp bacon mixture and leave to melt. Fry for about 1-2 minutes.
To serve place each fillet on a plate and spoon the brown-shrimp bacon butter over it.