Can you use the mandarin word 暖 to describe food or is it just to describe weather/climate/condition of the body etc?

For Chinese people, for most kinds of food or drinks, we like to eat while it’s still hot or cold, and though there are some foods, like bakes, cakes, etc., I think it’s good to eat it while it’s still warm; in this conditions most people will say “未(趁)(變)冷前較(最)好吃/未(趁)(变)冷前较(最)好吃 : to eat it before it turns cold” or “趁(熱)暖時較(最)好吃/趁(热)暖时较(最)好吃): It's better (the best) to eat it while it’s still hot(warm)”。
一点暖最好吃：it sounds weird, because “一點” means a little, “暖” means warm, (“暖”could be used in dishes thought not so often, and while describing the temperature of dishes or drinks, its meaning is clear enough), so we would don’t exactly know what It means.
暖(熱)一點最好吃/暖(热)一点最好吃：this is a normal and correct, but it means to eat it if the food temperature is a little higher than now it has.

Oh, it’s ok to say 有一點熱，which means close to too hot, and 有一點冷，means close to too cold, while to say 有一點暖，it means a little warm but not warm enough, and these three terms are commonly used to describe the weather or the feeling after puting clothes on or the temperature of the dish/drink as you mentioned, etc., but "一點暖(without 有 or even has 有)" is seldomed used to describe the temperature of dishes/drinks.

In your context, I think to say “溫溫的” or “有點溫” is fitted to what you are trying to express, and it means: medium warm or kind of warm.