Vegetables
Heat the olive oil or butter in a large skillet over medium heat.
Add the chopped onion, green bell pepper, and mushrooms if using.
Cook for about 5 minutes, stirring occasionally, until the vegetables soften and begin to develop a little color.
Step 2: Cook the Beef
Push the vegetables toward one side of the skillet.
Add the thinly sliced beef to the open side of the pan.
Cook until the beef is browned and fully cooked, breaking or chopping larger pieces into smaller bite-sized portions as needed.
Mix
