Along with what pps have said, I found it helpful to answer DS with a "yes" wherever possible. A positive response which can confirm the food is coming and that LO has been heard. I agree that it's too young to expect them to learn patience, but I don't think it is too young to begin teaching so long as expectations are low (very low). So perhaps a "yes" then follow up with what you are doing, "I am getting your food right now, it won't be long" or "It's right here, we just need it to cool down a bit before we eat" even guessing what she might be saying and echoing that back may help "you want me to hurry up, you really want your food now, hurry hurry mummy!".
I tended to offer something easy and immediate if mine was being fussy, like pp said, a bread stick or keep some pre-cooked pasta in the fridge which can be offered immediately.