Combine the Armagnac, maple syrup, cranberry syrup, thyme, coriander, and pepper. Marinate the foie gras scallops for 6 to 8 hours in the refrigerator. Remove the foie gras from the marinade and reserve marinade.
In a very hot saute pan, pan-fry foie gras for approximately 1 minute each side until golden brown. Salt lightly and place on a serving platter. Cover with plastic wrap. Refrigerate. Remove from refrigerator 20 minutes before serving to bring to room temperature.
In a saute pan over medium-high heat, add the butter and melt. Add the shallots and saute until translucent, about 2 minutes. Deglaze with white wine and cook until the liquid is reduced by half. Add the duck broth and reduce by 1/3. Add the reserved marinade, maple syrup, and fresh cranberries. Reduce until mixture thickens and then puree until velvety smooth. Add the lemon juice and salt and pepper, to taste.