Preheat the oven to 170C. And line a 8x8inch brownie tin with baking paper.

Combine the melted butter and brown sugar and stir until sugar starts to melt. Then whisk in the eggs and vanilla. Add the baking powder, baking soda and flour in and stir until just combined. Then finally stir through the rolled oats and choc chips.

Pour the mixture into the prepared brownies tin and smooth out the top with a large spoon or spatula. Bake in the oven for 20mins. Cool and then cut into squares.