In a mixing bowl, combine the olive oil, sugars, water and vanilla. Whisk until smooth and the sugars have dissolved.
Sift in the flour, baking powder, baking soda, and salt. Fold it all together with a spatula to make a soft, crumbly dough.
Now add the chocolate chips and work them into the dough either with the spatula or using your hands, which I found more effective. They may not fully mix in at this stage, don't worry.
Let the dough rest at room temperature for 15 minutes. It will look a little greasy, that's ok. At this stage you can chill the dough for 24 hours which is recommended but I personally didn't find it necessary. Read more in the post above.
Preheat the oven to 175 C. Line a baking tray with a silicone mat or non-stick baking paper.
Use a 1.5 tablespoon cookie scoop or a spoon to make 12 equal portions of the dough. Drop them onto the tray an inch apart and if they're not coming together or the chips are falling out, shape each one with your hands and the warmth of your fingers will bring them together. Flatten each one slightly because they don't spread much while baking. (If you did chill the dough then you'll need to spend a few more minutes shaping the dough balls).
Bake for 12 to 15 minutes, until browned on the edges but still somewhat puffy in the centers. The cookies will be very, very soft so leave them at room temperature on the baking tray for 10 to 15 minutes to firm up before transferring to a wire rack to cool further. If they seem very puffy, lightly press down on them with the back of a spoon. If you're baking chilled cookie dough, add 2 to 3 minutes to the baking time.
Once cooled, store in an airtight tin at room temperature for 3 to 4 days and in the fridge for 10 days, or the freezer for longer. I did find that the cookies become crunchier after two or three days so if you want them at their 'soft chewy centers' stage, eat them quick :) Happy baking!