Preheat your oven to 400°F (200°C). Toss the cubed potatoes with olive oil, garlic salt, and pepper until evenly coated. Spread them in a single layer in a greased 9x13-inch baking dish, making sure not to crowd them.

Bake the potatoes for 30 to 35 minutes, tossing halfway through with a spatula, until they are golden brown on the edges and fork-tender. The halfway toss ensures even browning.

While potatoes roast, pat steak cubes completely dry with paper towels. Season generously with salt, pepper, smoked paprika, and onion powder. Heat a large skillet over high heat until smoking hot, then add a splash of oil. Working in batches to avoid overcrowding, sear the steak cubes for 2 minutes per side until a deep brown crust forms but the center remains medium-rare to medium. Remove to a plate.

Reduce skillet heat to medium. Melt the butter and add the minced garlic, scraping up the browned bits from the bottom. Sauté for 1 minute until fragrant but not burned. Toss the seared steak back into the skillet briefly to coat in the garlic butter, then remove from heat.

When potatoes are done, remove from oven and pour the heavy cream evenly over them. Top with the garlic butter steak bites, scraping all the garlic butter from the skillet into the dish.

Sprinkle the shredded cheddar cheese evenly over the steak and potatoes. Return to the oven for 5 to 7 minutes, or until the cheese is melted and bubbly. Don't overbake or the steak will become tough.

Remove from oven and immediately garnish with sliced green onions and fresh parsley. Serve hot directly from the baking dish.