Roast the coriander and fennel seed, and then crush. Mix together with the sea salt, black pepper and orange zest. Brush the duck breast with some orange liqueur, and then pack the meat side with the herb/zest mixture. Wrap and refrigerate until ready to cook.
For the blood orange sauce: Combine the sugar, vinegar and shallots in a pot over medium-high heat and cook until reduced to a syrup. Add the orange liqueur to deglaze and continue cooking to reduce slightly. Add the duck stock and blood orange juice and continue simmering. Stir in the xanthan gum and simmer until thickened, and then season with salt and pepper. Strain the sauce and keep warm.
For cooking the duck: Heat a cast-iron plancha, griddle or skillet to high heat. Sear the duck fat-side down until crispy, about 12 minutes. Remove, brush off some of the herb/ zest mixture and continue to cook, meat-side down until medium rare. Serve with the blood orange sauce.
Cook Notes: Cook additional duck breasts to serve with the remaining sauce, or use for another recipe.
This recipe was provided by a chef, restaurant or culinary professional and may have been scaled down from a bulk recipe. The Food Network Kitchens have not it for home use and therefore cannot make any representation as to the results.