Makes 4 servings (4 kebabs)
Total time: 60 minutes
FOR THE SAUCE, COOK:1 cup diced onions
3 Tbsp. unsalted butter
3/4 cup ketchup
1/2 cup each fresh orange juice, cider vinegar, and bourbon
1/3 cup brown sugar
1/4 cup molasses
2 Tbsp. Worcestershire sauce
Salt and black pepper to taste
FOR THE KEBABS, THREAD:2 pork tenderloins, trimmed and cut into 3 inch cubes (3 lb.)
1 large red onion, cut into 1 1/2-inch thick half-moon rings
Place a strip of foil on grill to protect skewers, then preheat grill to medium-high.
Brush grill grate with oil.
For the sauce, cook onions in butter in a saucepan over medium heat until soft, 4–5 minutes. Stir in ketchup, orange juice, vinegar, bourbon, brown sugar, molasses, and Worcestershire; season with salt and pepper. Bring sauce to a boil, reduce to a simmer, and cook 10 minutes; let cool slightly, then purée with a handheld blender.
Reserve half the sauce for serving.
For the kebabs, thread pork cubes and red onion on double skewers; season with salt and pepper. Grill kebabs, covered, 3–4 minutes on one side. Baste kebabs with remaining sauce, then flip and grill 3–4 minutes more.
You can also make these for the same amount of time under your oven's broiler.
Baste kebabs again, flip, and continue cooking and basting until an instant-read thermometer inserted into the centers registers 145°, about 4 minutes more. Let kebabs rest 5 minutes before serving with reserved sauce.