Cook the sweet potatoes and carrots in boiling water strain, and mash. (carrots take longer to cook - you might want to cook them separately) Add oil and sugar, beat sugar and oil together in separate bowl and then add to rest of recipe, brown sugar can be used. Add the rest of the ingredients, mix and bake in 9 x 13 inch pan at 350ºF.  until done, about an hour but you need to check.