Preheat oven to 350 degrees then line a baking sheet with parchment paper.
Mix flour, baking powder, sugar, salt, pepper, onion powder and thyme together in a large mixing bowl until well combined. Add cold butter cubes then use a pastry cutter to cut butter into flour until slightly smaller than the size of peas.
Add grated Asiago cheese to the flour and butter mixture then stir to combine. Mix half-and-half or milk together with beaten egg then add to dry ingredients. Stir by hand just until combined and no dry spots of flour remain. The dough will be fairly sticky.
Scoop by heaping tablespoons onto prepared baking sheet, spacing at least 2" apart. If you would like the scones to be a bit more golden brown, brush top of each with a bit of extra half-and-half or a beaten egg yolk.
Sprinkle the tops with a bit more Asiago cheese then bake 18–20 minutes until golden brown and firm in the center. Remove from oven then brush with melted butter. Serve piping hot and enjoy!
One Last Thing
If you prefer light golden brown tops, just leave them as-is. If you like a darker top, just brush each of them with cream or egg yolk prior to baking.