01 -
Preheat the oven to 375 degrees Fahrenheit. Grease an 8 1/2 x 4 1/2-inch loaf pan and set aside.
02 -
In a large bowl, whisk together the flour, baking powder, onion powder, garlic powder, and kosher salt. Set aside.
03 -
In a separate medium bowl, whisk the eggs until slightly frothy. Add the sour cream and whisk until smooth. While whisking, slowly drizzle in the melted butter and continue whisking until combined.
04 -
Using a wooden spoon, stir the shredded cheeses and zucchini into the wet ingredients.
05 -
Add the wet ingredients into the dry ingredients. Stir together until all the flour is moistened. The dough will be stiff; use your hands for the final mix if necessary.
06 -
Place the dough into the greased loaf pan. Smooth out the top gently without compressing the dough into the pan.
07 -
Bake in the preheated oven for 50 to 55 minutes, until the top is firm, slightly domed, and deep golden brown. Cool in the loaf pan for 15 minutes, then transfer to a wire rack to finish cooling.