1. Preheat the oven to 450 degrees F. Line a large baking sheet with parchment paper or a Silpat baking mat and set aside.
2. In a large bowl, whisk together flour, baking powder, sugar, baking soda, and salt. Mix in cold butter with your fingertips until mixture resembles coarse meal. Stir in Cheddar cheese, Asiago cheese, and Parmesan cheese. Squeeze the grated zucchini in a paper towel to remove excess moisture. Stir into the mix. Add buttermilk and stir with a spatula until just combined.
3. Drop biscuit dough onto prepared baking sheet, about 1/4 cup per biscuit. Brush biscuits with melted butter. Bake for 10-12 minutes or until biscuits are set and slightly golden brown. Remove from oven and serve warm.
Note-you can use your favorite cheese. I like the combination of Cheddar, Asiago, and Parmesan, but feel free to mix it up!