Step 1: Place the pork and lamb in a large nonreactive bowl or baking dish. Sprinkle the sugar, curry powder, coriander seeds, peppercorns, and salt over the meat and stir to mix. Add the apricots, onions, orange zest, red wine, vinegar, and oil and stir to mix. Note: In the old days, Afrikaaners would add sour milk or heavy cream to the marinade for extra richness. Most younger grill masters omit it. I’ve made it optional, but I like the richness it adds.
Step 2: Marinate the lamb in the refrigerator, covered, for 2 to 4 hours-the longer, the richer the flavor.
Step 3: Meanwhile, cut the onion in half widthwise and cut each half in quarters. Break the quarters into individual layers.
Step 4: Drain the lamb in a large fine-meshed strainer over a large saucepan. Thread the marinated lamb and apricots and the onion layers and bacon strips onto the skewers to make kebabs, alternating the ingredients, beginning and ending with lamb chunks. Refrigerate until grilling.
Step 5: Boil the marinade over high heat until thick and reduced by one-third, 10 to 15 minutes. Whisk in the butter, apricot jam, brown sugar and additional teaspoon curry powder. If you used heavy cream in the marinade, add 2 tablespoons to the sauce. Continue boiling and whisking until the sauce is thick and richly flavored. Correct the seasoning, adding sugar or salt to taste: the sauce should be a little sweet and richly flavored. Pour of the sauce into a small bowl for basting.
Step 6: Set up your grill for direct grilling and preheat to high. Brush and oil the grill grate.
Step 7: Grill the kebabs until browned on the outside and the meat is cooked through, 2 minutes per side, about 8 minutes in all. After 4 minutes, start basting the sosaties with the sauce set aside for that purpose.
Step 8: Serve the sosaties at once. Unskewer the ingredients onto the plates and spoon some of the sauce on top, serving the remainder on the side.