In a small bowl, with a whisk, mix hoisin sauce, honey, ketchup, garlic and five-spice powder.
Brush each tenderloin with about 1 tablespoon of the glaze (set aside remaining glaze).
Put pork tenderloins on a grill in a broiler pan. Cook in a preheated oven at 375 F for 15 to 20 minutes or until the internal temperature reaches 160 F or pork tenderloins are cooked but lightly pink inside.
Meanwhile, in a small saucepan, mix the reserved glaze and water. Cook at medium-low, stirring from time to time, for 10 minutes or until the sauce has lightly reduced.
Remove the pork tenderloins from the oven and let rest 2 to 3 minutes.
With a sharp knife, cut pork tenderloins in fine slices and distribute in 4 plates. Salt, pepper and spread with warm sauce. It's ready to serve.