For the maple barbecue sauce:
- 1 cup ketchup
- 2 large cloves garlic, finely chopped
- 2 tablespoons dark brown sugar
- 1/4 cup dark amber maple syrup
- 2 tablespoons Worcestershire sauce
- 2 tablespoons cider vinegar
- 1 teaspoon allspice (1/3 palmful)
- Coarse black pepper
For the remainder of the sandwich:
- 1 large pork tenderloin (about 1 1/4 pounds), well-trimmed
- Extra virgin olive oil (EVOO) for drizzling
- Salt and pepper
- 3 tablespoons butter
- 2 small, firm Gala apples or other crisp apples, thinly sliced
- Freshly grated nutmeg
- 1 medium red onion, thinly sliced
- 1 large bundle watercress, trimmed and cleaned
- Juice of 1/2 lemon
- 4 crusty oblong rolls
- Sharp white cheddar cheese (optional)
- Pre-heat the oven to 425°F.
- Combine the ingredients for the barbecue sauce in pot and bring to a bubble, then reduce the heat to low and simmer gently for 20-25 minutes to thicken.
- At the same time, heat a grill pan or cast iron skillet to medium-high. Season the tenderloin well with salt and pepper and drizzle with EVOO. Cook over medium-high heat to brown all over, then transfer to the oven to cook through, 20-25 minutes.
- Melt the butter in a skillet over medium heat and add the apples. Season with nutmeg; add the onion, salt and pepper, then sauté to tender-crisp, 5-6 minutes.
- Dress the watercress with lemon juice, EVOO, salt and pepper.
- Slice the pork; arrange the pork on the rolls and top with lots of sauce or toss the pork slices in the sauce before piling on the rolls. Melt the cheese, if using, over the top of the pork under a hot broiler. Top with the apples, onion and watercress and set the bun tops in place.