I've never used a rack. Here is a very easy and good peach cobbler recipe if you'd like to give it a go. You can tweek it proportionally as you see fit based on the size of the oven or the thickness you want. I included some pictures so you can "see" rather than read the technique. or lack thereof.
10" Dutch Oven
1 stick butter
1 cup flour
1 cup sugar
2 tsp baking powder
1 cup milk
salt
1 can fruit
1/4 tsp vanilla
1 Melt butter in 10 inch Dutch oven.
2 Mix other ingredients in bowl.
3 Pour mixed ingredients into melted butter and add fruit but do not stir.
4 Place lid on Dutch oven, add coals, and cook until top is brown.
Placing bottom coals.
Butter
Pour the batter in and then pour the fruit trying to get it spread as evenly as possible over the whole mix. DO NOT STIR
Place lid on and lay coals on lid.
As the cobbler cooks, work the coals to the outside as the center will brown first and the heat is needed on the outside edge in order to get it brown also. Spin the lid 1/4 to 1/2 turn every 5 to ten minutes in order to eliminate hot spots, especially if there is a little wind.
After the cobbler has been cooking for about 15 minutes, start checking about every 5 minutes. When the cobbler starts to brown on top, remove the DO from the bottom coals and continue to cook until the desired color is achieved on the crust. At this point, remove the lid and remove the coals from it. When the coals are removed, replace the lid. Lid will still be hot and will still brown it a little more. If its going to be a while before serving and the top is browned as you wish, crack the lid so it doesn't sweat on the crust.
