In a large Dutch oven fry bacon until crisp, remove and drain. Discard all but 2 tablespoons of bacon fat. Add onions and cook on medium-heat until soft and translucent. Return bacon and add beans.
In a small pan combine vinegar, brown sugar, powdered mustard, garlic powder, salt and pepper. Simmer until sugar is dissolved and mixture begins to thicken. Add to bean and bacon mixture.
Cover and bake for one hour.
Notes
If you do not have an oven, you can use your Dutch Oven in the traditional manner, or simmer on the stove top or campfire on low, stirring frequently.