The ideal potluck or cookout dish is one that is easy to make in bulk and inexpensive, and doesn't degrade with extended heating or reheating.I nominate frijoles charros—Mexican cowboy beans cooked with onions, garlic, tomatoes, salted pork, and chilies—as one superlative potluck dish. It not only hits all of those criteria but also adds on "extremely delicious" for good measure.