Pat steak cubes dry and season generously with salt and pepper.
- Heat olive oil in a large skillet over medium-high heat. Add steak in a single layer and sear for 2–3 minutes per side until browned but still juicy. Remove and set aside.
- Reduce heat to medium, add butter, and stir in garlic. Cook for 30 seconds, toss steak bites in garlic butter, then remove again to rest.
- In the same skillet, melt butter and sauté garlic for 30 seconds.
- Pour in heavy cream and broth, whisking to combine.
- Stir in parmesan cheese until melted and sauce slightly thickens, about 3–4 minutes. Season with salt, pepper, and red pepper flakes if desired.
- Return steak bites to skillet, toss in sauce until warmed through.
- Garnish with fresh parsley and serve immediately with desired sides.