The first is correct of you are referring to fried chicken and lamb chop as a single dish and not 2 seperate foods. The second would be correct if you added an 's' to the end of lamb chop. "My favorite foods are fried chicken and lamb chops."

Food is uncountable in one meaning, but in this case food can also mean a dish (type of meal), which in this case is countable. The second sentence is correct, since you are talking about two separate foods, making plural. I assume you are counting fried chicken and lamb chop as separate meals. If you had a dish that consisted of fried chicken and lamb chop mixed together in one meal, then the first sentence would be correct, since you are talking about a singular food (dish). I doubt that this is the case, though.