Preheat oven to 350 degrees. Grease two bread loaf pans.
Mix all of the dry ingredients thoroughly in one large bowl.
Mix wet ingredients in another bowl. Combine two bowls, mixing gently just until there are no lumps. (I used a hand mixer for 20 seconds to remove remaining lumps.)
Add chopped quince; fold and pour into bread pans.
Bake for 60 minutes; depending on your oven, this could be a little less or a little more. Check with cake tester before removing from oven. Cool thoroughly before cutting.