Preheat the oven to 350°F (175°C) and line an 8x8 inch square baking pan with parchment paper.
In a large mixing bowl, combine the rolled oats, oat flour, baking soda, and sea salt.
In a separate medium bowl, whisk together the maple syrup, melted coconut oil, egg, and vanilla extract until emulsified.
Pour the wet ingredients into the dry ingredients and stir with a spatula until the mixture is uniform.
Fold in the dark chocolate chips until evenly distributed throughout the batter.
Transfer the mixture to the prepared baking pan and press down firmly using a spatula to create an even layer.
Bake for 18 to 22 minutes or until the edges are lightly golden and the center is set.
Remove from the oven and allow the bars to cool completely in the pan for at least 30 minutes before slicing into 12 rectangular bars.