Make sure you have thoroughly dried the zucchini to keep it from being too wet/watery in the finished bread. I do this using paper towels and squeezing the grated zucchini. (See video tutorial in post)
Preheat the oven to 325 degrees F. Lightly grease and flour one bread pan, 8.5 x 4.5 inch size.
In a bowl, whisk together the Greek yogurt, lemon zest, lemon extract, 1 large egg, coconut oil (measured when melted and cooled to room temperature), honey, and white sugar. Stir in the zucchini.
In a separate bowl, stir together the oat flour (measured AFTER blending. How to make oat flour: pulse regular old fashioned or quick oats in a blender or food processor until they resemble flour. Then measure and add to the bowl), white or white-whole wheat flour, baking soda, and salt.
Add the dry to the wet and mix until just combined. Over-mixing will result in dense bread.
Pour the mixture into the prepared pan.
Bake for 40-50 minutes or until a toothpick when inserted into the center comes out clean and the bread has begun to slightly pull away from the sides.
If needed tent some tin foil over the top to keep the top from over browning.
Remove, allow to slightly cool, and then invert onto a plate.
For the glaze: whisk together all of the ingredients and add lemon juice until you've reached desired consistency. You do want this glaze quite thick because it will melt over the hot bread.
Pour the glaze over the bread while still warm from the oven.