This is a hearty recipe full of vegetable chunks and tender beef cubes.
Combine flour, salt, thyme, marjoram and pepper in a large heavy-duty plastic bag. In batches, add beef cubes to flour mixture and toss to coat. Transfer to plate. In large nonstick skillet, heat half the oil over medium-high heat. Cook beef, in batches and adding more oil as needed, for 8 to 10 minutes or until browned on all sides. With slotted spoon, transfer to 3-1/2 to 6-quart (3.5 to 6 L) slow cooker.
Add beer and stock to skillet and bring to boil, stirring to scrape up any brown bits. Transfer to slow cooker. Add tomato paste, mustard, vinegar, Worcestershire sauce, onion, garlic, carrots and mushrooms to slow cooker, mix well.
Cook, covered, on LOW for 8 to 10 hours or HIGH for 4 to 6 hours or until vegetables are tender and stew is bubbling. Stir in sour cream just before serving. Serve with red wine and a French baguette.
* Percent Daily Values are based on a 2,000 calorie diet. Your daily value may be higher or lower depending on your calorie needs.