Boil the potatoes in salted water until tender. Drain, then mash with half the butter and all the heavy cream until smooth. Season with salt and pepper.

Steam or saute the green beans until crisp-tender. Set aside.

Heat olive oil in a large cast-iron skillet over high heat. Season the beef cubes generously with salt and black pepper.

Add the beef to the skillet in a single layer. Sear for 2 to 3 minutes per side until a brown crust forms. Reduce heat to medium.

Add the remaining butter and minced garlic to the skillet. Cook for 1 minute until fragrant, tossing the beef to coat.

Remove from heat. Sprinkle the grated cheese and fresh parsley over the beef, tossing well. Serve immediately over the mashed potatoes with green beans on the side.