Preheat
broiler. Broil pork, turning occasionally,
until cooked through, about 20 minutes.
Remove to a platter; cover to keep warm.
Meanwhile,
in a large skillet over medium-high heat,
melt 2 tablespoons of the butter. Add onions,
salt and pepper; cook until onions are golden,
about 10 minutes. Add sugar; cook until
onions are caramelized, 3 minutes longer
Add port, balsamic, blueberries and tomatoes;
bring to a boil. Remove from heat.
Thinly
slice pork and serve with sauce.
Per
Portion: 290 calories, 22 g protein, 11
g fat, 22 g carbohydrate, 439 mg sodium