Preheat the oven to 350 degrees F. Generously grease and light dust an 8-1/2x4-1/2-inchbread pan with flour and set aside.
In a large bowl, whisk 2 large eggs and 1 large egg yolk (discard white or save for another recipe). Add the lemon Greek yogurt (1 cup total), vanilla extract, almond extract, and coconut oil. Make sure to measure the coconut oil in its liquid form (Melt the coconut oil, measure, and then allow to slightly cool so you don't cook the eggs.).
Briskly whisk in the coconut oil with the other ingredients to combine well.
Zest and juice 1 large lemon. About 2 teaspoons zest and 2 tablespoons lemon juice is perfect! Add in the sugar and again mix until all ingredients are completely combined.
In the same bowl, add the oat flour. (To make oat flour: put old-fashioned or quick oats in a blender and pulse them until they resemble flour; measure oat flour after blending.)
Add the white or white whole wheat flour, cornstarch, baking powder, and salt to the oat flour. Pour 3/4 cup (100g) of blueberries on top of the flour mixture and lightly fold the blueberries into the flour on top and then mix everything together.
Mix together, very gently, until just combined (over-mixing will yield a dense bread and smashed berries).
Spoon 1/3 of the batter in the prepared bread pan and then place some of the reserved blueberries on top. Add another 1/3 of batter and place more blueberries on top. Finally, spoon the last 1/3 of the batter in the pan and place the final blueberries on top and slightly push under the batter.
If desired, sprinkle 1 tablespoon white sugar on top of the bread for a nice "crust"
Bake for 55-65 minutes or until a fork comes out clean when inserted into the center, or the bread starts to pull away from the edges. Tent the top with tin foil if the top of the bread is baking faster than the rest.
Remove from the oven and allow to cool before removing bread from the pan.
Store in an airtight container in the fridge.