Preheat oven to 400 degrees Fahrenheit (200 degrees Celsius).

Prepare a large frying pan. Score the duck breasts (lightly slice into the skin without cutting through to the meat). Season lightly with kosher salt and pepper.

Lay the duck breasts skin-side down in the frying pan. Turn heat to medium high. This will render the fat between the skin and the meat. Sear the duck for six minutes. Turn over and sear one to two minutes.

Transfer the duck breasts to a 9×13-inch (20 x 30cm) baking pan and bake for 7–10 minutes for medium rare.

In a large frying pan, combine the sugar, juice of one lemon, and water. Bring to a boil over medium heat, stirring until sugar is dissolved. (The result will be a lemon simple syrup.)

Lower heat to a simmer. Add lemon slices from the second lemon in a single layer and cook about 15 minutes. Turn slices occasionally.

Using tongs, transfer the lemon slices onto Gefen Parchment Paper to cool. Set aside, reserving the lemon simple syrup for the duck glaze.

Mix all ingredients in a small saucepan over low-medium heat. Stir until slightly thickened.

Lay seared duck breasts on a serving platter. Drizzle with lemon glaze. Top with candied lemon slices.