Heat the olive oil in a large skillet over medium-high heat until it shimmers, about 2 minutes.

Sear the sirloin pieces in a single layer, seasoning with salt and pepper. Cook for 2-3 minutes without moving, then flip and cook for another 2-3 minutes.

Remove the steak from the skillet. Lower heat and add unsalted butter to melt. Sauté minced garlic in the butter for about 1 minute.

Return the cooked steak to the skillet and toss gently in the garlic butter for about 1 minute.

In a separate saucepan, heat heavy cream over medium heat until it simmers gently, about 3-4 minutes.

Stir in the Parmesan cheese and garlic powder, stirring until the cheese melts into the cream, about 1-2 minutes.

Plate the steak bites, drizzle with the creamy parmesan sauce, and garnish with parsley.