If possible, take meat out 30 minutes in advance to bring up the temperature before browning.
Add oil to frying pan that will fit the roast. Sautè garlic cloves just until golden. Remove garlic.
In same frying pan, brown the roast on both sides.
Slice the onions length-wise. Either use baby carrots or slice large pieces of carrot. Keep them in large chunks, as both will be removed at end of cooking.
Place vegetables in bottom of the slow cooker.
Place the meat on top of the vegetables in the slow cooker.
Add the broth, and wine and make sure it comes up 3/4 of the way. If you are not using wine, add 2 tablespoons of Worcestershire sauce. If you will not be available to turn the meat, halfway through, add more broth or water to cover completely.
Cook at least 6 hours on medium In slow cooker, turning the meat at least once midway.