Preheat oven to 350ºF (180ºC). Grease a cookie sheet or use silpat.
Combine flour, baking powder, salt and butter with a pastry blender or in the food processor.
Mix in onion and cheese. Whisk egg with milk and stir into the mixture.
Drop 1 teasponful of batter on the cookie sheet or silpat leaving 1 inch between scones.
Bake in preheated oven for 15 – 20 minutes until golden on top.