This seriously simple soup is full of flavor and spice. You will need at least a 5-quart slow cooker for this reicpe. To save yourself some time in the morning, you can saute the ground beef, onion, garlic and celery the night before and refrigerate until the morning. Then all you have to do is combine the ingredients in the slow cooker in the morning and come home to a comforting, delicious meal. All you will have left to do is top it with some baked fresh corn tortilla strips, tortilla chips or corn chips and some sour cream, shredded cheddar cheese and green onion - or whatever you like! A nice side salad would be a wonderful accompaniment with this soup. This soup freezes well, also.