As it turns out, we can indeed add a grocery store of sorts. It's either very expensive, or very cheap depending how you look at it.
Each recipe in the creation spell is an additional layer. The pre-made keep design that the Priestesses of The Nature God have a magical plan for includes a simple creation spell with 8 layers, making only the essentials for the garrison to be stationed there.
It's meant to make a stew and bread, but it creates the individual ingredients for the stew, forcing the soldiers to cook their meals. I'm told they appreciate this, as it lets them get creative if they've got someone who can actually cook.
Later that Day
"As I mentioned, we can offer potatoes, corn, cabbage, onions, carrots, beef and lentils in bulk from the trading post. Free of charge to locals, but you'll need to supply the mana stones to power the spell." I explain to the local council later that day.
