Add the ○ dry ingredients to a bowl and use a whisk to mix together. Make sure there are no lumps.
Cut the butter into 1 cm cubes and cool. You can also use a chilled spoon to reduce their size before mixing them in.
Mix the butter in using a spatula in a cutting motion. Use your hands at the end to knead into a crumbly texture.
Make a depression in the center and add the whey (or milk) in 2-3 parts. Let it soak in without kneading. Gather it together in one lump and place in a plastic bag.
Stretch it out to a 1 cm thinness while still in the bag (it should be 15 x 20 cm large). Using a rolling pin helps things go more quickly. Let sit in the refrigerator for 1-2 hours.
Preheat the oven to 200℃. Remove the dough from the bag, and fold two or three times. Press down on it to get it to stick together.
Use a knife or a cookie cutter to make the individual biscuits. Brush milk on top, place on a baking pan lined with parchment paper, and bake at 200 ℃ for 18 minutes.
They're delicious hot from the oven! If they cool down too much, you can warm them up a bit and enjoy with butter or jam.
Story Behind this Recipe
I make these to use up whey that was left over from straining yogurt. Whey makes them soft and fluffy, but they're also pretty delicious with milk.
Sift the dry ingredients if you have time. When stretching out the dough, do so carefully so that you don't rip the bag. The bottom is prone to burning while baking, so bake on the top level. They're made sweet to be eaten as-is. If you're making them for breakfast, reduce the amount of sugar by half.