This is the most crunchiest cookies I ever owned. To give it a healthier bake, I adapted vegetable oil instead of the butter bravely, but it works wonderfully! It crumbles in your mouth straight away. —Mochi Mochi
Preheat the oven to 350°F/180°C/160°C (fan oven), or gas mark 4.
Put the vegetable oil, egg and sugar into a mixing bowl, use a hand whisk to beat until well combined.
Sift all the flour, baking powder and bicarbonate of soda together, add the chopped walnut in.
Add the dry ingredients into the wet ingredients, use spatula to mix until it forms a dough. It could be so crumbly, but that's what it is.
Take one small of the dough, roll into a ball shape and slightly press down to flatten it on the lined baking tray and repeat the rest of the dough.
Brush with a layer of beaten egg or milk. Bake in the preheat oven for around 15 to 20 minutes, depends how thick is your cookies, so better have a check after the first 15 minutes, and adjust the time to bake.