Cut steak into 2-3 inch pieces, rub evenly with 1-2 tablespoons avocado oil, then season all sides with blackened seasoning (mix smoked paprika, cayenne, onion powder, garlic powder, black pepper, salt, thyme, and oregano). Let sit at room temperature for 10-15 minutes.

Peel and quarter potatoes, place in cold water for 10 minutes to remove excess starch. Drain, then place in a pot of salted water and bring to a boil. Cook until fork tender, about 15-20 minutes.

Heat 2-3 tablespoons avocado oil in a large skillet over medium-high heat. Add steak pieces (work in batches to avoid overcrowding) and cook undisturbed for 2 minutes until golden brown.

Flip steak pieces once, cook 1 minute, then reduce heat to low and cook 1 more minute. Remove steak to a bowl.

Add 3 tablespoons butter and 1 tablespoon minced garlic to the same pan. Saute until fragrant, about 1-2 minutes. Return steak to pan, toss to coat in garlic butter, cook 1 minute more, then remove steak and tent with foil.

In the same pan, add 2 tablespoons butter and remaining minced garlic. Saute until fragrant, then slowly whisk in heavy cream. Bring to a simmer and reduce for 3-5 minutes.

Drain potatoes and mash with melted butter and warmed half and half until smooth. Stir in Monterey Jack cheese, garlic powder, salt, and pepper until creamy.

Add red pepper flakes, green onions, and Parmesan cheese to the cream sauce. Whisk until thickened. Taste and adjust salt and pepper as needed.

Serve steak bites over mashed potatoes and spoon Parmesan cream sauce generously over the top. Garnish with fresh parsley if desired.