Preheat oven to 400°(F). Line a large baking sheet with parchment paper or a non-stick baking mat; set aside. In a large bowl mix together 2 ½ cups of the flour, salt, baking powder, baking soda, and sugar.

Cut the butter into small cubes then quickly work it into the mixture (using your fingers) until it resembles a coarse meal.

In a small bowl, whisk together the egg and sour cream, then add to flour and butter mixture. In a small bowl combine remaining tablespoon of flour, grated zucchini, and a ½ cup of the cheese; toss to coat, then add to the scone mixture; gently fold them into dough with a spatula until combined.

Pour the shaggy dough out onto a clean, floured work surface and shape the dough.