Boil water in large pot for pasta.
Season steak tips with salt and pepper.
Heat olive oil in large skillet over medium-high heat.
Cook steak tips for 3-4 minutes per side.
Remove steak tips and set aside temporarily.
Add butter to the same skillet immediately.
Sauté minced garlic for 30 seconds until fragrant.
Cook rigatoni according to package directions exactly.
Drain pasta and reserve ½ cup pasta water.
Return steak tips to skillet with garlic butter.
Heat heavy cream in separate saucepan over low heat.
Add mozzarella and parmesan cheese to cream slowly.
Stir cheese sauce until completely smooth and creamy.
Combine drained rigatoni with cheese sauce gently.
Serve steak tips over cheesy rigatoni immediately.