Preheat the oven to 425F. On a parchment lined baking sheet, toss potatoes with olive oil and a pinch or two of salt and pepper. Roast for 20 minutes. Remove the potatoes from the oven, flip for an even crisp. Add the whole garlic cloves and roast an additional 15 minutes or until golden and crisp.
While the potatoes roast, toss the cubes of steak with salt to season. Heat a large cast iron skillet over medium-high heat with olive oil. When the oil shimmers, add the steak (in two batches if needed) and allow space between each piece. Without pushing the steak around, cook on each side for 3-4 minutes to develop a crust. Once all the steak is seared, return any steak from the previous cooking batch to the cast iron.
Add the butter, garlic, Worcestershire sauce and red pepper flakes. Cook down for 2 minutes, tossing the steak to fully coat in the garlic butter. Remove from the heat.
When the potatoes have finished roasting, sprinkle with parsley and top with the parmesan cheese.
Serve the steak alongside the garlic parmesan fries.