Pat the steak cubes completely dry with paper towels. Season generously with salt and black pepper on all sides.

Heat olive oil in a large skillet over medium-high heat until very hot. Add steak cubes in batches, leaving space between each piece. Sear for 2-3 minutes per side until golden brown and cooked to your preferred doneness. Remove each batch to a plate and tent with foil.

Reduce heat to medium. Melt 3 tablespoons of butter in the same skillet. Add 4 cloves of minced garlic and sauté for 30 seconds until fragrant. Return all steak bites to the pan and toss to coat in garlic butter. Remove from heat immediately.

In a separate saucepan over medium heat, melt 1 tablespoon of butter. Add 2 cloves of minced garlic and sauté for 30 seconds.

Pour in the heavy cream and bring to a gentle simmer. Cook for 2-3 minutes until slightly thickened.

Reduce heat to low and gradually whisk in the freshly grated Parmesan cheese. Continue whisking until the sauce is smooth and creamy, about 3-5 minutes. Season with salt, pepper, and red pepper flakes if desired.

Arrange steak bites on a serving platter. Drizzle with Parmesan cream sauce or serve sauce on the side for dipping. Garnish with fresh parsley and serve immediately.