Prepare the tarragon infusion as described for the classic method. Add 3 tablespoons (45 milliliters) glace de viande to the infusion, and reduce slightly until the mixture has a lightly syrupy consistency. Strain the mixture and whisk in 1½ ounces (45 grams) butter or Tarragon Butter. Finish with 2 teaspoons (10 milliliters) freshly chopped tarragon leaves.