Preheat oven to 140°C (284°F).

Combine oil, sugar, eggs, and vanilla in a bowl.

Mix wet ingredients well.

In a separate bowl, combine flour and baking powder.

Mix dry ingredients well.

Gradually add the flour mixture to the wet ingredients.

Mix until just combined; the dough will be slightly sticky.

Add chocolate chips (optional).

Grease a baking tray or line it with foil paper.

Form small balls of cookie dough using a spoon.

Place the dough balls on the prepared baking tray.

Bake for 15-20 minutes, or until golden brown on the bottom and soft on top.

Let cool slightly before serving.