Preheat oven to 350 °F. Grease 3 mini loaf pans.
Peel and core pears. Pulse in blender/food processor until they have "ground down" into very fine bits, but don't puree into "baby food" consistency. Measure out 1 1/2 cups of pears, and place in mixing bowl. Add sugar and shortening, and mix together thoroughly. Add pear juice and stir well.
In a separate bowl, combine baking soda, baking powder, xanthan gum, and flours. Add pear mixture to the dry goods, and mix well.
In a small cup (I use a coffee mug), combine 1/4 cup water plus egg replacer. Whisk with a fork, and then pour into bread batter. Fold/stir gently until it's mixed in.
Portion into pans, and bake for 35 minutes. (You can test with a wooden skewer; it should come out clean.) Remove from oven, and let cool in pan for about 10 minutes. (If you remove it too quickly, it may crumble; let it cool for a few so it can "set." If you prefer a softer crust, you can let it cool to room temperature in the pan; if you prefer a crisper edge, remove after 10 minutes.) Remove from pan and allow to cool.
Serve plain, or top with Jude's Birthday Frosting.
I would expect that it would make 12 regular sized muffins as well. I would bake them for approx. 18-20 min., and remove from pan after a 5 minute cooldown. It would also make a good "large loaf". Use a 9x5x3 pan (grease well) and bake 70-75 min., and allow to cool in pan for 10-15 minutes.
If you don't have a safe pear juice, use 1/3 cup water instead.
If you need to avoid egg replacer, I would add a little extra pear (or 1/4 cup applesauce or banana puree).
If you're using mini-muffin or even regular muffin tins, you probably could get away with skipping xanthan gum. I would not omit it if you are making mini or regular sized loaves.
If you're avoiding corn, check your ingredients to use corn-free pear juice (or apple juice/cider, if making that version) and baking powder. Use an alternate egg replacement.