Preheat the oven to 350° and spray a 9x5 loaf pan with non-stick spray.
Combine cheese: freshly grate sharp cheddar cheese and parmesan cheese and combine in a small bowl. Be sure to set aside about ¼ cup of the cheese blend for topping.
Wet ingredients: In a large bowl, combine butter, sugar, egg, and buttermilk until smooth.
Add dry ingredients: Stir in flour, salt, onion powder, garlic powder, baking soda, and baking powder. Mix until just combined.
Fold in Cheese and Bake: reserve ¼ cup cheese blend, add remaining cheese into the batter and lightly stir to combine. Spread the batter into the prepared loaf pan. Sprinkle the reserved ¼ cup of cheese on top.
Bake: Bake for 50-55 minutes or until lightly brown on top and toothpick inserted in the center comes out clean.