In small bowl, stir together flours, baking powder, baking soda, cinnamon, salt, and lemon zest.
In a larger bowl, beat together eggs, vanilla extract, stevia extract, monk fruit extract, and sour cream or yogurt until smooth.
Slowly stir dry mix into wet mixture.
Fold in zucchini and then fold in blueberries.
Divide batter between 12 greased or lined muffin tins.
Bake at 350°F for 25 to 30 minutes or until browned on top and toothpick comes out clean.
Cool for about 15 minutes in pan and then remove muffins from tins and cool on wire rack.
Store in refrigerator covered or freezer for up to 3 months.
Notes
Any sweetener can be used. To replace the stevia and monk fruit extracts, use about ¾ to 1 cup sugar equivalent.Zucchini muffins tend to stick to the muffin tin, so use silicone or paper liners for baking.Be careful when you mix the blueberries into the muffin batter. If you stir too briskly, the blueberries will turn the batter blue.Let the muffins cool before you remove them from the pan. They will be soft at first, so let them cool down before you attempt to take them out.