Our troop uses our week at summer camp to cover this. The patrol leaders make the newer scouts the head cooks toward the end of the week.
Our troop does not eat at dinning halls, we "outpost" for the whole week.
We have four patrols, and normally we get 5-6 new scouts each year, and they are divided up into exsisting patrols.
We also monthy camp, and have 6-7 other oportunities to cover this requirment through out the year. I'm sure there are many other troops like this.
At this time we have not used the new scout patrol, but are keeping our eye out, as we have an age gap, and currently getting a little heavy on older scouts (a good thing). But we tend to keep the scouts in regular patrols until age 16, as their needs and interest are differnt.