Preheat oven to 425°F. Oil and salt russet potatoes, then bake 50–60 minutes until fork tender.
Trim steak, cut into 2 inch cubes, toss with avocado oil, Cajun seasoning, and kosher salt. Rest 10 minutes.
Heat skillet with avocado oil. Sear steak bites about 2 minutes per side until browned.
Add butter and garlic, toss steak in garlic butter 1 minute, then transfer to a bowl.
In the same skillet cook butter and garlic, add cream, simmer 3–5 minutes, whisk in Parmesan and seasonings.
Slice baked potatoes, fluff inside, add butter, top with steak bites, and drizzle parmesan cream sauce.
Serve immediately while hot.