Combine the vegetable oil, milk, and sugar together in a bowl and mix with a whisk well.
Add in the flour and fold in with a rubber spatula.
Once it's no longer moist, pour the dough into a plastic bag. (Depending on the temperature and humidity, it may turn crumbly. Don't worry if it's a bit powdery.)
Fold the dough until it's no longer lumpy and then gently roll it out with a rolling pin. Be careful not to rip the dough. (This time I rolled it out to a 24 x 27 cm piece that was 1 mm thick.)
If the dough is too soft to handle, put it in the fridge for 10 minutes to rest.
Coat with the sugar and flour leaving about 2 cm of one side un-coated.
Starting from the side opposite of the uncovered side, roll up the dough. Then roll out the dough to 5 mm thick. (Sprinkle some sugar on top if you'd like.) Cut the dough into 5-6 mm wide slices with a kitchen knife.
Bake in an oven at 160℃ for 12-15 minutes and it's done! (I used a gas oven.)
You can also make different versions by using cocoa, kinako flour, coffee or tea leaves. It's also nice to make this with crystal sugar or raw cane sugar, instead of granulated sugar.
You can make this quickly whenever you feel like eating sweets. If you are making this as a gift, it tastes better if you use butter instead of vegetable oil.
In Step 2, I wrote, "fold it in," but to be honest, you can just mix the dough a bit. When you roll out the dough, it creates layers so it's going to be flaky. Since you coat the cookies with sugar, I reduced the amount of sugar in the dough to 20 g. Add more if you'd like. I use 10 g of sugar for the dough, and coat it with a lot of granulated sugar.