Combine water, 2/3 cup onions, 1/4 cup maple syrup, 1/4 cup salt, bay leaf and garlic in a large bowl or large sealable plastic bag. Add pork chops; turn to combine. (If brining in a bag, place the bag in a large bowl.) Marinate in the refrigerator, turning the meat once or twice, for 2 to 8 hours.

Whisk raspberry (or red-wine) vinegar, 2 tablespoons maple syrup, 1 teaspoon thyme, 1/8 teaspoon salt and pepper together in a medium bowl. Add 2/3 cup onions; toss to coat well. Refrigerate, stirring once or twice, while the pork is brining.

About 15 minutes before you're ready to cook the pork chops, combine 1 1/2 cups raspberries, the remaining 2/3 cup onions, wine, 2 tablespoons maple syrup, balsamic vinegar and 1/4 teaspoon pepper in a blender or food processor. Blend or process until pureed. Pour the sauce through a fine-mesh sieve into a small bowl; stir and press on the solids to extract all the sauce. Stir in the remaining 1 teaspoon thyme.

Remove the pork chops from the brine and pat dry. (Discard brine.) Sprinkle both sides with the remaining 1/8 teaspoon salt and a generous grinding of pepper.

Place a large cast-iron or heavy-bottomed skillet over medium-high heat until hot enough to sizzle a drop of water on contact. Add oil and tilt the pan to coat the surface. Add the pork chops and cook until browned, 2 to 3 minutes per side. Transfer the chops to a plate; tent with foil to keep warm.

Reduce heat to medium, add the raspberry sauce and boil, stirring constantly, until the sauce is reduced by half, about 3 minutes. Taste and add 1 to 2 tablespoons maple syrup if the sauce is too tart.

Return the chops and any accumulated juices to the pan and cook on medium heat, turning the chops to coat with the sauce, until they register 145 degrees F on an instant-read thermometer, 1 to 2 minutes.

Drain the pickled onions (discard the pickling mixture or save for another use). Gently toss with the remaining 1 1/2 cups raspberries. Serve the chops with the pan sauce and top with the pickled onions and raspberries.

MAKE AHEAD TIP: Brine pork chops (Step 1) for up to 8 hours. The brined chops, patted dry, can be wrapped in plastic and refrigerated for up to 2 days.