Pulse the flour and butter in a food processor until they start to look like breadcrumbs. Tip into a bowl and make a well in the middle.
In another bowl, beat the eggs and milk with a fork, add a good pinch of salt and pepper and pour into the well. Mix the flour into the eggs and milk, adding a little more milk if needed, until you have a soft, dry dough.
Split the dough evenly into 3 pieces. Press each piece out flat on your work surface and sprinkle 1 piece with mustard powder, 1 with cumin powder and the last with grated cheese. Roll up each piece and knead lightly until the flavouring is just mixed in, trying not to handle the mixture too much.
Press or roll the dough pieces flat again, until they are about 2.5cm thick. Cut out 2 circles from each piece with an 8cm cutter or the rim of a glass, and place upside down on a baking sheet. Brush the top of each scone with the extra milk and bake in the oven for 15 minutes, until risen and brown.