In a saucepan, combine the tomatoes, tarragon, shallots, vinegar, and wine, and bring to a boil. Reduce the heat to medium-low and simmer until reduced to a thick syrup and dark brown, about 20 minutes. Remove from the heat and add the parsley. Let cool while making the hollandaise sauce.
In a stainless steel bowl set over a pot of simmering water over medium heat, whisk the egg yolks with the lemon juice, water, mustard, salt, and cayenne together until pale yellow and slightly thick. (Be careful not to let the bowl touch the water.) Remove the bowl from the pot and whisking vigorously, add the butter, 1 teaspoon at a time, until all is incorporated. Add the tomato mixture to the sauce and whisk together until well blended. Place over a pot of warm water, off the heat, and cover to keep warm, stirring occasionally until needed.
Yield: Makes about 2 cups