Heat oven to 375°F / 200°C
Line 1 or 2 baking sheets with parchment paper.
Mix together the flour, baking powder, and salt. Mix in the butter with your fingers or a pastry knife until incorporated.
Add the cheese and mix well.
In a separate bowl whisk together the yogurt, eggs, and mustard.
Make a well in the flour and cheese mixture and pour in the egg mixture. Blend with a pastry knife until you've got a good dough.
Pull off some dough and mix into equal, round, rough balls on your baking tray. My wife got 14 good sized scones. Size of the balls was maybe like the size of a racquetball or a lacrosse ball.
Bake for 20 minutes, turning half-way through, until a toothpick stabbed in comes out clean.
Serve warm or cooled with butter, jam, or chutney.