Prepare pizza dough.
Preheat grill a high as you can get it or put pizza stone in oven and preheat at 450 for 30 minutes.
Rinse and trim stems up to leafy area. Discard bottom inch of stem. You can maintain stems, by cutting them in 2 inch pieces and cooking a little earlier. I usually don’t keep stems. . If you keep the stems, chop into 2 inch pieces and put into boiling water 3 minutes before adding in rest of broccoli rabe.
Submerge in large pot of boiling water for 5 minutes. Place in ice bath to keep green color, while preparing next step.
Saute pancetta in medium heat frying pan until fat in rendered and it’s is cooked through. Remove from pan and use same pan to saute broccoli rabe.
Saute garlic in same pan used to cook pancetta. Drain broccoli rabe and cut into 3 inch pieces and saute for a few minutes. Add red pepper flakes and salt to taste.
Roll out dough to the size of dinner plate. Arrange mozzarella cheese, pancetta, and broccoli rabe.
Bake for 8 minutes or until bottom is crisp.