Preheat oven to 350°F and set out a cookie sheet lined with aluminum foil
Use a paper towel to pat dry duck. Using a sharp knife, score four ¼-inch-deep cuts across the duck skin at a 45-degree angle. Sprinkle ¼ teaspoon salt and pepper over the meat side of each duck breast.
Heat a heavy pan over high heat. When pan is hot, add duck breasts to the dry pan, skin side down, and cook for approximately 5 minutes, or until skin is brown and crispy. Flip and cook for 2 more minutes.
Remove pan from heat, reserve the drippings in pan, and transfer duck breasts, skin side up, to cookie sheet. Bake on the top rack of the oven for about 7 minutes for medium rare, or to your desired degree of doneness.
While duck is roasting, carefully discard all but two tablespoons of duck drippings from the pan. Return pan to medium heat and add shallot. Stir occasionally for 3 minutes, or until shallot begins to turn golden. Remove from heat, Add vinegar to the pan and stir with a wooden spoon to loosen up the browned bits left by the duck. Add jam, Cassis, and remaining teaspoon of black pepper. Return to heat and stir occasionally for 3 minutes. Reserve.
Remove duck from the oven, cover with aluminum foil, and let rest, for 5 minutes. Slice each breast at a 45-degree angle into ¼-inch-thick strips (properly cooked duck should resemble medium-rare steak). Arrange in a fanlike pattern on a warmed plate and spoon cassis compote overtop. Serve immediately.