Unpack the boneless lamb breast from NEGANTIgardi, pat it dry, and let it come to room temperature for half an hour to an hour. This is very important, as it will make the cooked meat juicy. If using a cut that has been flash-frozen, transfer it from the freezer to the refrigerator the day before to let it thaw, or soak it in cold water for two hours, then follow the same procedure as with fresh meat. Thanks to flash-freezing technology, the meat will taste as if it were freshly cut.
Preheat the oven to 150 degrees if using the convection setting (with a fan).
Rub the meat slices with salt and pepper, then fry them in a pan until golden brown.
Place half of the onion, finely sliced, in a baking dish, and arrange the browned meat slices on top. Then sprinkle the remaining onions and bay leaves on top. Cover the dish with foil and bake in the oven for three hours.
Then transfer the meat to another baking dish, cover it with foil, and return it to the oven for an hour, reducing the temperature to 140 degrees and continuing to cook.
Drain the onions in a colander, remove the bay leaves, and return them to the pan. Skim the fat from the liquid and pour it back into the pan. Reduce the liquid by half, then add the chopped anchovies and two teaspoons of wine vinegar. Finally, stir in the parsley.
When the lamb breasts are ready, remove them and place them in a separate dish, cover with foil, and let them rest for 20 minutes.
Slice the chicken breast and arrange it on a plate along with the onions.