Combine the oats, chocolate chips and brown sugar in a bowl.
Add the melted butter and mix well to combine
Pour into a lined 20cm by 20cm baking dish.
Press down with the back of a spoon to push all the ingredients together, spreading out to the edges, and making it even.
Bake at 190°C, (375°F) for 15-20 minutes, until the mixture is golden and bubbly.
Remove from the oven and allow to cool completely before cutting into 20 squares.
Notes
Storing: these are fine in the fridge for 3-5 days. Otherwise they also freeze well.Substitutions: swap the oats for quinoa flakes to make them gluten free