Soak 2 tablespoons (30 milliliters) each white and dark raisins in ¼ cup (60 milliliters) port. Heat the mixture on the stove for 5 minutes to soften the raisins—do not let it boil. Add 5 fluid ounces (150 milliliters) game or other brown stock to the port-raisin base. Instead of adding demi-glace, add ¼ cup (60 milliliters) glace de viande and 2 teaspoons (10 milliliters) gastrique. Reduce the sauce slightly, until it has a lightly syrupy consistency. Finish it by whisking in 2 ounces (60 grams) butter and 2 tablespoons (30 milliliters) toasted pine nuts.