Put a small sauté pan over a low flame and heat 2 Tablespoons of oil. Add the Breadcrumbs and cook stirring till they just begin to color. About 3-5 minutes. Transfer to a cool plate immediately and set aside.
Put a large saute pan with a lid over a medium-high flame and heat 2 more Tablespoons of the oil. Lower the flame to medium and add the garlic, anchovies and red pepper flakes. Saute until the anchovies begin to break down.
Add in the broccoli rabe and salt as desired. Saute until the broccoli rabe begins to wilt. Add in the water and cover the pan. Cook until the broccoli rabe is tender, about 10 minutes.
Bring a pot of generously salted water to a boil. Drop in the penne and cook until al dente. Drain the pasta and add it to the pan. Toss for 1-2 minute over a medium flame.
Serve in warm bowls with a sprinkle of the Toasted Breadcrumbs.