Weigh & cube the butter & leave till softened. If you forget to take the butter out to soften, here’s a hack I reviewed to soften butter in about 10 minutes. Add the sugar to the butter in your mixing bowl & give a light mix together. Then mix on low speed with a stand/hand mixer until light and fluffy, (known as ‘creaming the butter & sugar’). You can of course do by hand with a spoon and some elbow power!
Line baking sheets/trays with baking/parchment paper and grease in place if the trays do not have a lip (or you could lose your biscuits).
Sieve in the flour, corn flour/starch into the sugar/butter mixture. Mix in by hand, don’t use a mixer .
Use a Pastry Cutter/blender for this next part- incorporates the flours into the butter/sugar mixture much more easily & is quicker, (especially if your hands hurt) Push the pastry cutter down on the bottom of the bowl, rotating left & right. Do this to all the mixture until the butter had taken on all the flour. Alternatively, do this ‘cutting in’ process, using 2 butter knives. Note that the mixture will not come together into a ball at this stage. It will be very crumbly & that is fine.
In the bowl or on a large sheet of baking/parchment paper, very gently knead the dough just until it starts to come together, and no more. Form the dough into a very rough square shape, by using you hands & pressing down. Push in the end pieces to make sure the ends are the same height as the middle of the dough. Do until the dough is about ½cm (5mm or ⅕in) thick. Alternatively, place baking/parchment paper on top of the dough and roll out.
Trim around the dough until you have a straight square shape. Place the scraps of dough, back in the bowl. Cut down the middle of the dough, and then cut ‘slabs. I got 18 slabs, (1½ – 2cm, approx. ⅔ – ¾" wide & about 8cm/3" long). Try to cut a little thinner than you would want, as they spread a little on baking.
Very carefully transfer them with a palette knife to the prepared baking trays/sheets, leaving a good 2½cm/1" gap at least, in-between. Make holes with a fork all over the slabs, but very carefully not to go too far down & break them.
Using the scraps left over, gently squash the dough together into a ball & flatten into a disc shape, pushing up the edges to make an even thickness. Cut this disc into 8 pieces. Using your thumb & index finger, pinch the ends of the round dough to give a decorated edging & shape known as Petticoat Tails. Carefully transfer the dough to the baking tray & make holes with a fork over the dough. Alternatively, make some more ‘slab’ shapes.