1-First step: marinate the chicken
Start with 1 package of thin sliced boneless skinless chicken breasts, about 1 pound. Place the chicken in a bowl or resealable bag and coat it with the herb and garlic marinade. Let it sit for at least four hours, or better yet, overnight. This resting time matters because it helps the chicken soak up flavor and stay juicy on the grill.
If you are cooking for a busy week, this is a great make-ahead step. You can marinate the chicken in the morning and grill it later that night, which makes dinner feel much easier. For best results, keep the chicken chilled while it marinates.

2-Second step: trim and blanch the broccoli rabe
Trim 1 to 2 inches off the stems of the broccoli rabe. Bring a pot of salted water to a boil, then cook the broccoli rabe for about 1 minute. This quick blanch softens the greens while keeping their color and bite.
Right after boiling, move the broccoli rabe into ice water. This stops the cooking fast and helps keep it from turning dull or mushy. Drain it well and pat it dry so it is ready for the skillet.

3-Third step: cook the garlic and greens
Heat extra virgin olive oil in a skillet over medium heat. Add the sliced garlic and optional red pepper flakes, if you want a little heat. Cook until the garlic starts to brown, but do not let it burn.
Then add the broccoli rabe and toss it in the oil until heated through. Finish with the juice of 1/2 lemon, then season with salt and pepper to taste. The lemon brightens the greens and gives the sandwich a fresh lift.

4-Fourth step: grill the chicken
Heat your grill to medium. When the grill is ready, cook the marinated chicken for 3 to 5 minutes per side, or until fully cooked. Thin sliced chicken cooks quickly, so keep an eye on it to avoid drying it out.
Once cooked, transfer the chicken to a plate and let it rest for a few minutes. This short rest helps the juices settle so each bite stays tender. If you are serving a mixed group, you can also grill extra chicken to use in salads or wraps later.

5-Fifth step: toast the rolls
Place the wheat sub rolls on the grill for 1 to 2 minutes. Toasting them gives the bread a little crunch and helps it stand up to all the layers inside. It is a small step, but it makes a big difference in texture.
If you are making this recipe for students or busy parents, this quick toast also makes the sandwich feel more like something from a deli, without adding much work.

6-Final step: assemble and serve
Slice the rolls open and build each Garlic Herb Grilled Chicken Sandwich in layers. Start with broccoli rabe, then add the grilled chicken, prosciutto slices, roasted red peppers, and fresh mozzarella. Drizzle balsamic vinegar on top if you want a little sweet tang.
Layering the ingredients this way helps spread the flavor evenly through the sandwich. The hot chicken and greens gently soften the mozzarella, and the roasted peppers add color and sweetness. Serve right away while the rolls are still warm and the cheese is just starting to melt.
Layering matters here. It is the easiest way to get garlic, herbs, creaminess, and tang in every bite.