Shred zucchini, using a cheese grater, leaving skin on
Press liquids from zucchini, blotting with paper towel. Salt and pepper zucchini just a bit, toss and allow to sit for 10-15 minutes, blot mostly dry.
In a mixing bowl, combine flour, salt, pepper, onion powder, baking powder and baking soda and whisk until blended.
Add in cheeses and zucchini.
Whisk together milk, egg and melted butter in a small bowl and add to mixing bowl. Stir until combined.
Line a loaf pan with parchment paper and bake for 50-60 minutes on the middle rack.
Rest for 5 minutes, lift bread from pan, slice and serve with or without butter.