Prepare the steak and mushrooms.
Season the beef with salt and pepper.
Heat a skillet over medium-high heat.
Add 2 tablespoons of butter and let it melt.
Cook the steak bites for 3-4 minutes, turning as needed.
Remove the steak bites and set aside.
In the same skillet, add the garlic and sauté until fragrant.
Add the sliced mushrooms and cook until they are browned.
Return the steak bites to the skillet and add the remaining butter.
Toss to combine and adjust seasoning.
Garnish with fresh parsley before serving.