Yes, vegetables can be added to this dish. Bell peppers, snow peas, canned baby carrots, and broccoli are all great choices. Vegetables will add more liquid to the crock pot, so additional cornstarch may be needed to thicken the sauce. Dense vegetables such as carrots and broccoli can be added in the beginning but all other vegetables can become soggy if cooked too long. Most vegetables can be added the last hour of the cooking process.