Preheat oven to 350F. Grease one 9x5-inch loaf pan ( you an also split the batter into two pans, just be sure to adjust the baking time)
In a large bowl, whisk together the egg, brown sugar, coconut oil, granulated sugar, sour cream and vanilla extract. Add flour, baking powder, baking soda, and cinnamon, and fold into mixture.
Add the zucchini, bananas, and blueberries, and fold gently to combine.
Turn batter out into the prepared pan, smoothing the top lightly with a spatula.
Bake for about 65 -80 minutes or until the top is golden, the center is set, and a toothpick inserted in the center comes out clean. Allow to cool in pan for 15- 20 minutes until transferring to a wire rack.
*NOTES: All zucchini and bananas are different in the amount of moisture in them. Your batter should be on the thicker side. The zucchini will release water into the batter as it bakes. You may add additional flour to batter before cooking if needed. It's better to have your batter be too thick than thin. I also suggest you place your grated zucchini between paper towels and press firmly to remove as much moisture as you can. Bake as long as needed and place a piece of foil on top of the bread if the top is beginning to brown.