Tip: Put beef fat in your cholent. Make sure it's the white fat the type that will render down, and NOT the silver skin/connective tissue. Where I live some stores sell little bags of it, and it's real cheap. I also have beef fat from when I trim a rack of ribs, it's how I get every pennies worth. Just put a couple of pieces in and it will give your cholent an incredibly rich and delicious flavor, because as they say fat is flavor.
Don't put any oil in your cholent the fat will melt and make your cholent oily just with real beef flavor.
My cholent is as simple as can be but very delicious! All I put in it is beans, barley, flanken, beef fat, potatoes, onions, garlic and kishke. I spice it with salt and pepper. It is simple but like this i get the most beefy flavored cholent, and not one diluted with random sweeners ie ketchup, or diluted with some vegetable oil.