Step 1: Prepare the Beef

1. Season the beef strips with a pinch of salt and black pepper.
2. Heat 1 tablespoon of olive oil in a large skillet over medium-high heat. Sear the beef in batches, cooking for 1-2 minutes per side until browned but not fully cooked. Remove the beef from the skillet and set aside.

Step 2: Cook the Vegetables

1. In the same skillet, heat the remaining olive oil and butter over medium heat. Add the chopped onions and sauté for 3-4 minutes until softened.
2. Add the mushrooms and cook for an additional 5-7 minutes, stirring occasionally, until the mushrooms are tender and golden brown.
3. Stir in the minced garlic and cook for 1 minute until fragrant.

Step 3: Make the Sauce

1. Sprinkle the flour over the vegetables and stir well to coat. Cook for 1-2 minutes to eliminate the raw flour taste.
2. Gradually pour in the beef broth, whisking constantly to prevent lumps. Add the Worcestershire sauce and Dijon mustard, stirring to combine.
3. Bring the sauce to a gentle simmer and cook for 5 minutes until thickened.

Step 4: Combine the Beef and Sauce

1. Return the seared beef to the skillet, along with any juices from the plate. Simmer for 3-4 minutes, or until the beef is tender and cooked through.
2. Reduce the heat to low and stir in the sour cream, mixing until the sauce is smooth and creamy. Adjust seasoning with additional salt and pepper, if needed.

Step 5: Cook the Egg Noodles

1. While the stroganoff is cooking, bring a large pot of salted water to a boil. Add the egg noodles and cook according to the package instructions, usually 8-10 minutes. Drain and toss with butter and a pinch of salt.

Step 6: Serve the Dish

1. Plate the buttered egg noodles and spoon the beef stroganoff over the top. Garnish with chopped parsley and a sprinkle of paprika for a pop of color. Serve immediately.