Preheat oven to 350 degrees F (175 degrees C). Lightly grease a large cast iron skillet.
In a large bowl, beat together the eggs, oil, vanilla, and sugar. Fold in the zucchini. Beat in the flour, salt, baking powder, baking soda, and cinnamon. Gently fold in the blueberries. Transfer to the prepared skillet.
Bake 50 minutes in the preheated oven, or until a knife inserted in the center of a loaf comes out clean. Cool 20 minutes in pan, then turn out onto wire rack to cool completely.
Southern Honey Butter
1 Cup Softened Butter
4 Tablespoons Sweetened Condensed Milk
8 Tablespoons Honey, Or To Taste
Place the butter, milk, and honey into a food processor or blender. Process until the mixture is smooth and has turned a light cream color. Refrigerate until ready to serve.