If you are making egg-free cookies, in a small bowl mix the flax meal and water, set this aside while preparing the other ingredients.
In a medium-sized bowl, whisk the GF flour, starch, baking soda, and salt together.
In a glass bowl or jug, heat the butter in the microwave for about 30 seconds or until it is at least 90% melted. Add both of the sugars, vanilla, and an egg or the flax "egg" and whisk until smooth.
Pour the wet mixture into the dry one and mix with a spatula, until a smooth slightly runny dough forms. Fold 1 cup of chopped chocolate/chips into the dough, and add more if you wish.
Cover the bowl with a lid or plastic wrap and set this in the fridge for about 30 minutes (you can also just let it sit in the fridge for a couple days until you are ready to bake). Line a baking tray with parchment paper, scoop dough balls (of your desired size) onto the tray and place them into the freezer until they are quite firm (maybe about 20-30 minutes, or keep them in there for future emergency cookies).
Once the dough balls are chilled, preheat your oven to 350 degrees fahrenheit (177 degrees celsius). When the oven is heated, remove the cookie tray from the freezer, arrange them so they won't ooze into each other, and bake for 8-10 minutes (you’ll need to bake them longer if you’re making big cookies) or until the edges are golden brown and the center looks soft and kind of gooey/unbaked. Remove from the oven, and let them cool for at least 4 minutes before eating. Enjoy!