Add 2 tablespoons canola oil to pan, and swirl to coat.
Add onion and garlic; saut 5 minutes, stirring constantly.
Add sugar and the next 10 ingredients (through star anise); bring to a boil. Reduce heat, and simmer, partially covered, for 30 minutes or until plums break down and sauce thickens, stirring occasionally. Discard cloves and anise.
Preheat oven to 45
Heat a large skillet over medium-high heat.
Add 2 tablespoons oil to pan; swirl to coat.
Sprinkle pork evenly with 1/2 teaspoon salt and 1/2 teaspoon black pepper.
Add pork to pan; saut 7 minutes, turning to brown on all sides.
Transfer pork to a foil-lined jelly-roll pan; coat with 1/2 cup plum sauce. Roast pork at 450 for 15 minutes.
Remove pork from oven. Turn pork over; coat with an additional 1/2 cup plum sauce. Roast 10 minutes or until a thermometer inserted in thickest portion of pork registers 15
Remove from pan; let stand 10 minutes. Slice crosswise.