Delicious Beef Stroganoff

Name: Delicious Beef Stroganoff
Prep time: 15 min
Total time: 15 min
Cuisine: European, Eastern European
Ingredients: 1 kg Quality Mark blade steak; 1 onion, cut into thin wedges; 2 cloves garlic, crushed; 200g Swiss brown or button mushrooms, thickly sliced; 2 Tbsp tomato paste; 1 cup beef stock; 1 Tbsp Dijon mustard; 1 Tbsp flour; ½ cup sour cream; Pasta or rice to serve; Fresh parsley, chopped (optional)