Step 1: Set up your grill for direct grilling and preheat to high.
Step 2: Peel the onions, leaving most of the stem end intact. (The helps hold the onion together during cooking.) If you’re feeling ambitious, toss the onions with olive oil, salt, and pepper. Grill the onions until well browned on all sides, 3 to 5 minutes per side. For ease in turning, you may wish to thread the onions on bamboo skewers before grilling. You can grill the onions at a previous grill session. This step is optional, but it will give the sauce a rich smoke flavor.
Step 3: Place the onions (grilled or raw if you’re omitted the previous step) in a large deep saucepan and add the wine, vinegar, honey, and 3 tablespoons butter. Bring to a boil over high heat. Boil the sauce until the onions are tender and the wine, vinegar, and honey have cooked down to a syrupy glaze, 6 to 10 minutes. If the onions become soft before the sauce has thickened, transfer them to a plate with a slotted spoon, and continue boiling the sauce until thick and syrupy, then add them back. Correct the seasoning, adding salt to taste and vinegar or honey as needed. The onions should be a little sweet, a little sour, and very flavorful. The onions can be cooked several hours or even a day ahead and reheated just before serving. Just before serving, stir in the remaining 1 tablespoon butter. You should wind up with about 1-1/4 cups.
Step 4: Set up your grill for direct grilling and preheat to high. Have one grill zone on medium. (See Box on Three Zone Grilling on page 000.) Brush and oil the grill grate.
Step 5: Generously season the chops on both sides with salt and pepper. (OK, I know they add the salt after grilling in Tuscany and they don’t bother with pepper. But I still maintain you get a better crust when you the season the meat just prior to grilling.)
Step 6: Arrange the chops on the grill grate running on the diagonal to the bars of the grate. Grill until nicely browned on the outside and cooked through, 4 to 6 minutes per side, depending on the desired degree of doneness. Give each chop a quarter turn half way through on each side to lay on a crosshatch of grill marks. If the chops brown too much on the hot zone, move them to the medium zone.
Step 7: Transfer the chops to a platter or plates. Reheat the onion mixture. Spoon it over the chops and sprinkle with the parsley if using. Serve at once.