Simple Classic Beef Stroganoff

Ingredients

• 1 1/2 pounds filet or ribeye, cut into thin slices.
• 8-ounces cremini or button mushrooms, sliced
• 2 tablespoons olive oil
• 1/2 teaspoon salt
• 1/2 teaspoon black pepper
• 2 tablespoons butter
• 2 tablespoons flour
• 1/2 yellow onion, minced or thinly sliced
• 1 3/4 cup beef stock
• 2 teaspoons Worcestershire sauce
• 1/2 tablespoon Dijon mustard
• 3 tablespoons sour cream
• 2 tablespoons fresh chopped parsley, for garnish