Preheat oven to 180 degrees C. Grease a 20x30cm baking tray.
In a large bowl, stir together the eggs, brown sugar, white sugar and vanilla. Add the oil and mix to combine.
In a separate bowl, combine the flour and the oats. Gradually stir flour mixture into egg mixture 1/2 cup at a time, stirring until completely mixed. Fold in chocolate chips. Spread the mixture evenly onto a baking tray.
Bake in the preheated oven for 13 minutes. Remove from oven while still slightly gooey and let cool for 3 minutes before cutting into squares. Then cool on a wire rack for 10 minutes. Store in an air-tight container.