Bring a pot of salted water to a boil.
Add green beans and cook for 4 to 5 minutes until crisp-tender.
Drain green beans and set aside.
Heat butter or olive oil in a large skillet over medium heat.
Add minced garlic and sauté for 30 to 60 seconds until fragrant, avoiding browning.
Pour in heavy cream and stir gently.
Add shredded cheese and stir until melted and smooth.
Season sauce with salt, black pepper, and onion powder if using.
Add cooked green beans to the skillet and toss to coat evenly with the sauce.
Cook for 1 to 2 minutes until heated through.
Serve warm, garnished with optional Parmesan, lemon zest, or parsley.