Put rack in center of oven and preheat to 400F. Whisk flour, baking powder, salt, onion powder, thyme, and sage in a large bowl to blend.

Crumble the butter into small bits without melting it. This can be difficult. Oddly a cheese grater seems to work well. Mash this into the dry mix with your fingers, again without melting the butter (somehow) until it resembles coarse meal. Whisk the egg & milk together in a small bowl and add to the meal. Mix with a fork until it's all moist and a bit sticky.

Turn the dough out onto a floured work surface and fold it 4 times, just enough for it to come together. Gather into a ball, then flatten to a 3/4" (about 2cm) round. Use a biscuit cutter dipped in flour to cut out rounds and place them on a slightly greased baking pan, spaced an inch or so apart. Gather the dough scraps into a ball and repeat until it's mostly gone. If you like, brush the tops of the biscuits with milk/butter.

Bake about 22 min until golden on top. Transfer to rack and serve.