1. Prep Your Ingredients

Start by gathering all your ingredients to make the process smooth. Wash the bunch of broccoli rabe thoroughly under cold water, then trim off the tough ends of the stems. Cut the broccoli rabe into roughly 2-inch pieces to ensure even cooking.

Pound the two 4oz chicken breasts thinly between plastic wrap or parchment paper using a meat mallet or rolling pin. This helps them cook quickly and evenly. Chop two cloves of garlic and finely mince or grate the third clove. Pick the leaves from the rosemary sprig and chop them finely, as rosemary is potent and a little goes a long way.

Slice the fresh mozzarella ball into thin pieces, enough to top each chicken breast generously. Toast or warm the crusty Italian rolls or focaccia rolls in a toaster oven or skillet for extra crunch. Season everything lightly with salt and pepper as you go.

2. Infuse the Oil with Garlic

Heat a large skillet over medium heat and add 2 tablespoons of olive oil along with the two chopped cloves of garlic. Let the garlic sizzle gently in the oil without browning too quickly. This infuses the oil with garlic flavor, which is key to the dish’s taste.

Stir occasionally and wait until the garlic becomes lightly golden and fragrant, about 1-2 minutes. Add a pinch of hot pepper flakes right away to bloom their flavor in the warm oil. This step takes patience but builds the base for the broccoli rabe.

3. Cook the Broccoli Rabe

Once the garlic and pepper flakes are ready, add the prepared broccoli rabe to the skillet. Place a lid on top and let it wilt for about 1 minute. The steam helps it soften quickly without sticking.

Remove the lid, toss everything together, and add about 1/2 cup of water. The water not only aids cooking but also helps mellow the natural bitterness of broccoli rabe by allowing it to evaporate. Season with salt and pepper to taste.

Cook over medium heat for 7-10 minutes, stirring occasionally, until the broccoli rabe is soft and cooked down significantly. It reduces in volume a lot, perfect for topping sandwiches. Taste and adjust seasoning if needed. Remove to a plate and keep warm.

4. Marinate the Chicken

While the broccoli rabe cooks, prepare the chicken marinade in a shallow dish. Combine the finely minced or grated garlic clove, chopped rosemary leaves, 1 tablespoon of balsamic vinegar, a pinch of salt, and pepper. Mix well with a fork.

Add the pounded chicken breasts to the marinade, turning to coat both sides. Let it sit for just a few minutes while the skillet preheats again. This simple marinade adds tangy, herby flavor that elevates the chicken.

5. Sear the Chicken Breasts

In the same skillet used for the broccoli rabe, add 1 teaspoon of olive oil and heat over medium-high. The residual flavors from the greens make the chicken even tastier. Place the marinated chicken in the hot skillet.

Cook for 3-4 minutes per side until golden and fully cooked through. The thin pounding ensures quick cooking without drying out. Check the internal temperature reaches 165°F if you have a thermometer.

6. Assemble and Melt the Cheese

Top each cooked chicken breast directly in the skillet with the reserved broccoli rabe, dividing it evenly. Layer slices of fresh mozzarella over the broccoli rabe. Cover the skillet with a lid to trap steam and melt the cheese until gooey, about 1-2 minutes.

The combination of juicy chicken, garlicky greens, and creamy mozzarella creates the perfect filling. Turn off the heat once melted to avoid overcooking.

7. Build the Sandwiches

Open the toasted crusty Italian rolls or focaccia. Place one chicken breast with toppings on the bottom half of each roll. Squeeze the sandwich gently to let juices soak in.

Top with the other half of the roll and serve immediately while hot. Cut in half if desired for easier eating. Enjoy the burst of flavors in every bite.