Preheat the oven to 180°C (160°C fan) and line two baking trays with baking paper.
In a large bowl, mix together the oats, flour, baking powder, cinnamon, salt and sugar.
In a separate bowl, whisk together the oil (or melted butter), egg, maple syrup and vanilla.
Pour the wet ingredients into the dry ingredients and mix until a soft dough forms.
Fold through the chocolate chips. Use your hands to bring the dough together.
Scoop or roll the mixture into 16 balls and place on the prepared trays. Gently flatten each one with your hand or the back of a spoon, I like to place a round cookie cutter over each ball and mould them to get a nice round shape.
Bake for 12–14 minutes, until lightly golden around the edges. The centres will still feel soft.
Leave to cool on the tray for 5 minutes before transferring to a wire rack. They'll firm up as they cool.
Tips: Delicious with a glass of cold milk.
Add 2 tablespoons of pumpkin or sunflower seeds for extra crunch.
Sprinkle a pinch of flaky sea salt over the cookies before baking for a delicious sweet-salty finish.
Freeze the cookie dough balls and bake straight from frozen, adding 2–3 minutes to the cooking time.
Storage: Store in an airtight container for up to 5 days, or freeze the baked cookies or unbaked dough balls for up to 3 months.