For this quest you have to gather information and says you should go to the kitchen. More description it does not have.
So what to do?
Go to the kitchen area in the main town, in the right corner in the back is a npc that gives you food. Do not apply the food.
Go stand at the tent lines, so the 2 big warrior's can't see you. If they see you, you will fail.
Where the 2 big warrior's stand are some wooden crates. On one of them is sitting a little girl.
Target this girl. You will see it has a buff (empty plate or full plate).
You also see a female waitress walking around the big table.
What you need to do is:
Pick the food of the npc, do NOT use it yet.
Stand at the tent lines so you can see the girl on the crate, but the warrior's don't see you.
Target the girl.
When the girl has a free plate buff and the female waitress is at her the buff of the girl goes to full plate. When this buff changes you need to run fast to her and directly apply your own food and STAND STILL. You only have 3 seconds for this.
If you are not in time (so better run when the waitress gets there), you are too late with applying food, the warriors saw you, or you moved you failed the quest. Only thing you can do then is to go back to the npc to get new food and retry.
This quest can be done without speed potions, and it is not a favorite quest in game.