Add onion, orange juice and garlic to a blender or food processor and mix until thick paste forms.
Pour paste into a small saucepan and add all remaining ingredients (except pork loin).
Simmer over medium heat for about 5 minutes or until heated through.
Cut 1" slits down top and bottom of pork loin in at about 1 1/2 inch intervals.
Spread some of the paste along the bottom of the roast, making sure to get some in the slits.
Place roast in foil-lined baking pan (paste-side down). Spread remaining paste along top of pork loin, making sure to get some in the slits. Use up all the paste to fully cover the loin.
Cover with foil and bake for 45 minutes.
Remove from oven, uncover and pour out the liquid.
Increase oven temp to 450F and bake, uncovered for an additional 15 minutes, or until internal temp reaches 155F.
Remove from over and tent with foil for approximately 5 minutes.
Slice and serve!
Nutrition Info Per Serving: Calories 346.5 Total Fat 11.1 g Saturated Fat 3.9 g Polyunsaturated Fat 1.1 g Monounsaturated Fat 4.5 g Cholesterol 159.8 mg Sodium 122.6 mg Potassium 889.5 mg Total Carbohydrate 6.4 g Dietary Fiber 1.3 g Sugars 3.0 g Protein 52.5 g