Combine paprika, chili powder, salt, and pepper in a small bowl. Rub the mixture into the beef on all sides. Sear the brisket in a nonstick pan on high heat for 2 minutes on each side (make sure the pan is hot before adding the meat). 

Place the cooked brisket in a Crock-Pot, and fill the pot about 1⁄2 way with water. Add celery, cabbage, tomatoes, onions and garlic (you can also add some more salt and pepper if you want to). 

Set Crock-Pot on high for 30 minutes. Reduce heat to medium or low and allow to slow cook for 6-8 hours, basting and turning the brisket periodically. 

Cube the brisket, and refrigerate or freeze leftovers in handy zip-lock bags. Makes 4 servings of protein and vegetables. Enjoy!