Pastry flourWhat you are looking for is a prepared mix not flour. A donut mix you can add just water to contains flour(s), sugar(s), oil, emulsifiers, flavors and sometimes many other ingredients. Pillsbury comes to mind but if you are not a large buyer you won't get far. Start with a local bakery supply house. Someone like Dunkin Donuts makes their own mixes and probably won't sell you bag. Sometimes you see donut stands at fairs, etc. You could ask where they buy their mixes.