Preheat oven to 425 degrees.  Line a baking sheet with foil (for easy clean-up).  Wash, dry and cut potatoes into one inch cubes. In a mixing bowl combine the tarragon, garlic, paprika, cayenne pepper, mustard and one tablespoon of the olive oil.  Toss the potato cubes with the herb mixture.  Pour out onto the baking sheet in a single layer.  Bake for 30 minutes.  Remove from the oven and drizzle the remaining tablespoon of olive oil, return to the oven for 10 additional minutes.  Serve