Pat the steak cubes very dry with paper towels. Season generously with salt and pepper.

Heat 2 tablespoons olive oil in a large skillet over medium-high heat until shimmering.

Add steak in a single layer (work in batches if needed). Sear 2–3 minutes per side until deeply browned. Remove seared cubes to a plate and keep warm.

Reduce heat to medium. In the same skillet, melt 3 tablespoons butter and add 4 cloves minced garlic. Sauté for about 30 seconds until fragrant—don’t let it burn.

Return the steak to the skillet. Toss quickly to coat in the garlic butter and warm through for 30–60 seconds. Remove from heat and cover loosely.

In a separate saucepan over medium heat, melt 1 tablespoon butter. Add the 2 cloves finely minced garlic and cook for 20–30 seconds.

Pour in 1 cup heavy cream and bring to a gentle simmer (not a rolling boil). Simmer 2–3 minutes, stirring to prevent skin forming.

Lower heat and whisk in ½ cup freshly grated Parmesan until the sauce is smooth. Season with salt, black pepper, and a pinch of red pepper flakes if using.

If sauce is too thick, thin with a tablespoon of milk or cream.

Spoon the sauce over the steak bites or serve it on the side. Garnish with chopped parsley and serve immediately.