Apple Sauce??

technically 'apple sauce' is unsweetened pureed apples. So if you can find unsweetened canned/jar apples and put them in a blender, you could use that. Or just buy apples, peel and core them chop up, and simmer for a few hours until they cook down. Cool and refrigerate.

I do make blueberry muffins and replace the oil with applesauce. Still use a bit of butter for the taste.
Thee baked goods do tend to be a bit moister, so you may want to cut back a tad on the apple sauce (if the recipe calls for 1/3 cup of oil, use 1/4 cup).