Heat large saucepan over medium-high heat, add 2 tablespoons canola oil to pan swirl to coat. Add onions and garlic; sauté for 5 minutes stirring constantly. Add plums, sugar, rice wine vinegar, ketchup, soy sauce, dry mustard, ground ginger, black pepper, crushed red pepper, cloves, and anise. Bring to a boil.
Reduce heat and simmer, partially covered for 30 minutes stirring occasionally. Cook until the plums have broken down and the sauce thickens. Discard cloves and anise.
Preheat the oven to 450°
Heat a large skillet over medium-high heat, add 2 tablespoons oil to the pan; swirl to coat. Sprinkle pork evenly with ½ teaspoon salt and ½ teaspoon black pepper. Add pork to pan, sauté 7 minutes, turning and browning on all sides.
Transfer pork to a foil lined cookie sheet; coat with ½ cup of the plum sauce. Roast pork at 450° for 15 minutes. Remove pork from the oven, turn it over and coat with an additional ½ cup of plum sauce.
Roast 10 minutes or until thermometer inserted in thickest portion of the pork registers 155°. Remove from pan; let stand 10 minutes.
Slice cross wise. Serve with remaining plum sauce.