Trim both the ends of green beans. If can also cut the beans in half instead of keeping it full.
Heat butter and oil in an oven-safe skillet (preferably cast-iron skillet).
Add green beans to the hot skillet. Season it with salt and pepper. Mix well.
Cover and cook on medium heat for 5 minutes.
Remove the lid. Add minced garlic and toss well. Cook for another 30 seconds until the garlic has browned.
Switch off the flame. Sprinkle parmesan cheese and mozzarella cheese. Broil @200 C for 2-3 minutes until the cheese start to bubble.
