Instead of cooking meat introduce a way to preserve vegetables

In example:
8 Stones
1 cooking pot
0.5L Water
Canning jar
Vegetable of all kind

Create a fireplace kit, add 8 stones, add cooking pot, add water to the cooking pot, add Tomatos to canning jar and put it into the cooking pot
Lets say 2 Tomatos = 1 canning jar
1 Paprika = 1 canning jar
1 Pumpkin = 2 canning jar