Halve, pit, and thinly slice the peaches to yield approximately 2 cups. Place slices in a bowl and gently toss with 0.5 tablespoon lemon juice and a pinch (about 1/8 tsp) of salt to brighten flavor and prevent browning. Set aside for 5 minutes to macerate.

Make the peach vinaigrette

Reserve 3–4 small peach slices and finely dice them. In a small bowl whisk together reserved diced peach, 1 tablespoon olive oil, 1 tablespoon white balsamic vinegar, 1 teaspoon honey, 1/2 teaspoon Dijon mustard, 1/4 teaspoon black pepper and 1/4 teaspoon smoked paprika until emulsified. Taste and adjust salt (add up to 1/4 tsp more if needed). This will be used as both dressing for arugula and a finishing drizzle for the sandwich.

Prepare other produce

Thinly slice 1/4 red onion into rings. Halve, pit and slice or fan the avocado; toss avocado slices lightly with remaining 1/2 tablespoon lemon juice to prevent browning.

Toast the rolls

Heat a skillet over medium heat and add 1 tablespoon unsalted butter. Split ciabatta rolls and place cut-side down in the skillet until golden and slightly crisp, about 1–2 minutes. Remove and keep warm.

Warm the turkey and melt cheese

In the same skillet over low-medium heat, arrange two slices of smoked turkey per sandwich, top each stack with a slice of provolone (or havarti). Cover briefly with a lid for 30–45 seconds to help the cheese melt, then remove.

Dress the arugula

In a medium bowl toss the 2 cups baby arugula with 1 teaspoon of the peach vinaigrette (reserve remainder for drizzle). Season lightly with a pinch of salt and pepper.

Assemble the sandwiches

On the bottom halves of the toasted rolls layer: a handful of dressed arugula, turkey with melted cheese, 1/2 of the macerated peach slices, a few avocado slices, and a couple of thin red onion rings. If using, add 1 tablespoon pickled jalapeños per sandwich for a bright spicy note. Drizzle about 1/2 tablespoon of the reserved peach vinaigrette over the fruit and avocado.

Finish and serve

Top with the other roll half, press gently, and cut sandwiches in half on the diagonal. Serve immediately while the bread is warm and the cheese is melty. Makes 4 sandwiches.