Pat steak cubes dry with paper towels and season generously with salt and black pepper.
Heat olive oil and 2 tablespoons butter in a large skillet over medium-high heat.
Once hot, add steak bites in a single layer. Cook 3-4 minutes, turning occasionally, until golden brown. Work in batches if needed.
Remove steak to a plate and set aside.
Reduce heat to medium, add remaining butter and minced garlic. Sauté 1 minute.
Pour in heavy cream, bring to simmer. Add Italian seasoning.
Stir in Parmesan until melted and sauce thickens.
Return steak to pan, toss to coat.
Garnish with fresh parsley before serving.