Prepare vegetables; chop carrots, celery and onion. Scrub and cube potatoes into bite sized pieces. Mince garlic. Add all vegetables to the bowl of a 5-6 quart slow cooker. Sprinkle vegetables with the spices.
Heat a large skillet over medium-high heat with 1 1/2 tbsp olive oil. Meanwhile, cut beef into bite size pieces.
When skillet is hot, add half of your meat. Brown on each side. Add to slow cooker and repeat with remaining meat and olive oil.
Pour beef broth and Guinness over meat and vegetables. Cover and cook for 5 hours on high or 10 hours on low.