Trim off bottom 1-2” of broccoli rabe. Once boiling, add broccoli rabe and cook for 4 minutes, or until tender. Drain and rinse under cold water.
Using a colander and several paper towels, press as much water as possible out of the broccoli rabe. Chop into ~1” pieces and set aside.
Meanwhile, place Italian sausage in a large skillet over medium heat. Cook, stirring occasionally to break up sausage, for 5 minutes.
Add olive oil, garlic and red pepper flakes; stir until well combined. Sauté for 1 minute, stirring occasionally.
Add chopped broccoli rabe, stir until well combined and continue sautéing for 2-3 more minutes.
Remove skillet from heat and add lemon juice; stir until well combined. Set sausage mixture aside to cool.
For the Cheesy Bread
Preheat oven to 350°F.
Slice loaf of bread in half lengthwise; place each half on separate pieces of aluminum foil.
Brush tops of both halves evenly with the Italian dressing.
Sprinkle half of mozzarella cheese evenly on top of both halves.
Divide the sausage and broccoli rabe mixture evenly on top of both halves.
Wrap foil over bread and crimp edges together. Place both pieces of wrapped bread on baking sheet.
Bake for 10 minutes.
Carefully remove baking sheet and open foil.
Using a small bowl, combine the Pecorino cheese, Italian seasonings, garlic powder and remaining mozzarella cheese. Sprinkle this mixture evenly on top of each piece of bread.
Return to oven and continue baking uncovered for 5-6 minutes, or until cheese has completely melted. (Note: If desired, broil the bread for the last 1-2 minutes.)
Remove loaves from oven and sprinkle with red pepper flakes and chopped Italian parsley.