In a small bowl, mix olive oil, soy sauce, orange juice, dijon mustard, honey, garlic powder and pepper.
Spray a shallow glass baking dish with cooking spray and place pork tenderloin in dish. Cover with honey dijon mixture and rub well into pork. You can sprinkle some extra garlic powder and black pepper on if you like. Keep remaining mixture set aside.
Place in oven on middle rack and back for 35-40 minutes. Carefully baste with more of the honey dijon mixture every 10 minutes for an amazing baked on glaze. Use a baster or brush to do this.