Sort the spinach, wash well and drain. Peel onions and garlic, dice finely. Sauté garlic and 1/3 onions in hot fat. Add the spinach and let it collapse. Season and drain if necessary
Wash and dab the fillets and cut them in half lengthwise. Season fillets, roll them up and pin them with wooden skewers
Boil up wine, 1/8 l water, lemon juice and peppercorns. Add stock. Cover the plaice rolls in the stock and cook over a low heat for about 5 minutes
Finely dice the bacon and leave it crispy. Add the rest of the onions and fry until golden brown. Put the spinach in a greased casserole dish. Drain the plaice rolls and place on the spinach
Sieve the stock, bring to the boil and thicken with sauce thickener. Stir in sour cream. First mix the egg yolks with some sauce, then stir into the sauce (do not boil any more!). Season to taste with salt and pepper
Pour sauce over the plaice rolls. Sprinkle bacon-onion mixture over it. Bake in the preheated oven (electric cooker: 225 °C / convection oven: 200 °C / gas: level 4) for approx. 15 minutes. Served with mashed butter potatoes