Heat your oven or oven toaster to 300F/150C. See steps below if making regular cookies.
If using flax meal or ground flax for the egg substitute, mix the flax seed/ground flax seeds in a small bowl with the water. Leave to thicken in the refrigerator for 10 minutes.
In a large bowl, mix together all the dry ingredients. Make sure that there are no clumps of baking soda!
Mix together the oil, milk, and vanilla extract.
Add the flax "egg" or mashed banana into the oil-milk mixture and then mix well.
Add in the wet mixture into the sugar. Mix until it’s well-incorporated.
Create a well in the centre of the flour mixture then pour in the wet sugar mixture.
Mix everything well until there are no more signs of dry flour.
Fold in the chocolate chips. You’ll have a thick and sticky cookie dough!
Brush a thin layer of oil on your skillet. Add in the cookie dough and spread evenly on the skillet. Top with more chocolate chips, if you’d like! If you’d like, you can also opt to bake some individual cookies! See the steps for regular cookies below.
Bake the skillet cookie for 18 to 20 minutes or until the cookie is golden brown and crisp on the outside.
The middle will still be chewy and gooey, and that’s how it’s supposed to be. Note that if you use a larger skillet, the cookie dough will be thinner and have a cakier middle when spread on the skillet. It'll also cook faster so adjust the baking time accordingly.You can check the doneness of the cookie by poking the center with a toothpick. If it comes out clean, it's ready! Leave the skillet it to cool for around 10 minutes and then scoop over your favourite vegan ice cream. Scoop some of the ice cream with the cookie! Enjoy!
If making a thinner skillet cookie, you can fill your skillet around 1/3 full. This will yield a thinner cookie but will be more cooked through and less gooey on the inside!
This is the thinner cookier after baking.