Preheat a panini press. In a large skillet, heat 1 tablespoon olive oil over medium-high heat. Add the garlic and cook until softened, about 2 minutes. Transfer the garlic to a food processor or mini chopper. Add 2 tablespoons water to the skillet, then add the broccoli rabe in batches, allowing each batch to wilt slightly before adding the next. Cook, stirring frequently, until crisp-tender, about 3 minutes; season with salt and crushed red pepper.
Add the sun-dried tomatoes and 4 tablespoons olive oil to the garlic and process to form a paste. Add the pine nuts and parmesan cheese and pulse until the pine nuts are finely chopped.
Brush each slice of bread on one side with the remaining 3 tablespoons olive oil and place oiled side down on a work surface. Top the bread with the sun-dried tomato pesto. Divide the broccoli rabe among the 4 slices of bread and top with the provolone. Set the remaining bread slices in place, oiled side up.
Working in batches, grill the sandwiches in the panini press until the bread is crisp and golden, about 1 minute.