"To conjure food requires a different incantation than any other conjuring charm we use. Does anyone know why this is?"
"Food is an exception to Gamp's Law of Essential Transfiguration," Lily answered.
"That's right. So we can't conjure it out of thin air like we could, for example, water, even though we can consume it. If we wanted to eat dirt or another basic element, we can conjure that with one of the generic spells, but food requires more specificity."
Professor Flitwick pointed at his desk, waved his wand, and said an incantation. A large plate of miniature tarts appeared on his desk, and the class was immediately riveted.
"I managed that by arranging with the house-elves in advance that I would be taking this plate, focusing on where I wanted to conjure it from, and using the spell. It's more of a translocation spell than strict conjuring, but in practical use they are very similar." He wrote the incantation on the board, then said, "Given what we've learned in the past about conjuring, I want you to use this incantation and try to conjure just one tart to your own desk."
There was a rustling as wands were taken out and students prepared to do the spell. After a short while, Lily's muttered incantation resulted in a tart popping onto her desk.
"Well done, Miss Evans!" Mr. Flitwick smiled at her. "You may eat your spoils."
The class watched jealously as Lily delicately devoured her tart.
"Bet I can get more than one tart," James muttered to Sirius.
"Bet I can get more than you." The race was on.
Sirius succeeded first, successfully conjuring two tarts onto his desk. Before Flitwick could protest, he'd jammed them both into his mouth. "Ha ha," he garbled, spitting crumbs onto James' desk.
"You know what?" James said. "I see your two tarts and I raise you...the whole kitchen."
"Like to see you try," Sirius said, still muffled.
James thought about the kitchen, and the food he knew was there. He closed his eyes, concentrating, then said the incantation firmly, waving his wand in exactly the proper form.
"James Potter, what have you done?"
He opened his eyes at Professor Flitwick's outraged tones, and laughed when he saw that he had indeed brought up the whole kitchen, or at least most of the food. Tarts, roast beef, mashed potatoes, pies, biscuits, sandwiches -- all were piled haphazardly around the classroom and everyone was eyeing them greedily.
"I conjured enough for everyone," James said innocently, then picked up the nearest tart and took a bite. "And if you want my advice," he added to the class at large, "you'll dig in while you can."
None of the boys needed telling twice, and started tearing into the food. When James offered Lily a sandwich, she responded by pushing a pie into his face.
"That's what you get for one-upping me," she said smugly. Then she licked the cream off her fingers.