“I thought it was very fun to make and it was the perfect amount of challenging to make. I thought it was delicious and amazing.” — Sami, recipe tester, age 11
Adjust oven rack to middle position and heat oven to 350 degrees. Spray inside bottom and sides of 8½-by-4½-inch metal loaf pan with vegetable oil spray.
In medium bowl, whisk together flour, baking powder, salt, and pepper (if using). Use rubber spatula to stir in cheddar cheese and ½ cup Parmesan cheese, breaking up clumps, until cheese is coated with flour.
In large bowl, whisk milk, sour cream, melted butter, and egg until well combined.
Add flour mixture and use rubber spatula to gently stir until just combined and no dry flour is visible. Batter will be heavy and thick—do not overmix.
Use rubber spatula to scrape batter into greased loaf pan and smooth top. Sprinkle remaining ½ cup Parmesan cheese over batter.
Place loaf pan in oven. Bake until top of cheese bread is golden brown and toothpick inserted in center comes out clean, 45 to 55 minutes.