• Cook the lentils with the bay leaf in salted water on a low fire for 20-30 minutes.
• Finely dice the onion and sauté in hot butter. Salt and pepper, add a dash of port wine and reduce. At the end mix in the lentils and let stand for a few minutes.
• In the meantime, cut the skin of the duck breast crosswise with a sharp knife to create a checkered pattern. Place skin side down in a pan and fry slowly over medium fire until the skin is wonderfully crispy. Put the thyme sprigs in the pan.
• Salt and pepper the meat side. After about five minutes, turn the duck breast over and fry gently on the meat side.
• Place on a preheated plate in the oven preheated to 100 degrees Celsius and let it simmer for 15 to 20 minutes until the meat is juicy and pink through and through.
• Drain and save the duck fat. Deglaze the meat stock with the broth, pour in the port wine, reduce by half and then add a piece of butter.
• Season this aromatic sauce with salt, pepper and a dash of dark, mild balsamic vinegar.
• Also in the meantime, boil a potato in salted water. Allow to cool slightly, cut into centimeter-sized cubes and fry until golden with two tablespoons of duck fat in a non-stick pan. Then salt and pepper.

Serving:

• Cut the duck breast diagonally into thin slices. Pile a bed of lentils in the middle of the plate, arrange the duck slices on top and drizzle with the sauce. Scatter the crispy potato cubes around it.