Place soy sauce, brown sugar, sherry, dried onion, cinnamon, olive oil, and a touch of garlic powder in a large resealable plastic bag. Seal, and shake to mix. Place pork in bag with marinade, seal, and refrigerate for 6 to 12 hours.
Preheat grill for high heat.
Lightly oil grate. Place tenderloins on grill, and discard marinade. Cook 20 minutes, or to desired doneness. Slice into medallions, and serve.
Serving Size 4
* Percent Daily Values are based on a 2,000 calorie diet. Your daily value may be higher or lower depending on your calorie needs.
The whole list of marinade ingredients is included in the nutrition facts for this recipe. The amount of marinade actually ingested will vary depending on factors like marinating time, ingredients, cooking style, etc.