How to Make It
Preheat the oven to 350°. Mix 1/4 teaspoon each of the honey and sugar with 2 tablespoons of the grapefruit juice. Brush on the duck.
Heat an ovenproof large skillet. When the pan is hot, add the duck breasts, skin side down, and sear over low heat until browned, about 6 minutes. Turn the breasts and cook for 2 minutes, then roast in the oven for 5 minutes. Let the duck rest on a cutting board for 4 minutes, covered loosely with foil.
Meanwhile, in a small nonreactive saucepan, mix the remaining 1/4 teaspoon sugar and 1 1/4 teaspoons honey with 1 tablespoon of the duck fat from the pan. Cook until the mixture is light brown, then add the stock, cream, thyme and the remaining 1/2 cup grapefruit juice. Simmer over moderate heat until reduced to 1/2 cup. Stir in the butter and grapefruit sections and season with salt and pepper. Remove from the heat.
Thinly slice the duck breasts and arrange on warmed plates with the pancakes. Top with the grapefruit sauce and serve.