Preheat oven to 350 degrees

Line a 9×9 baking dish with parchment paper

In a large bowl, mix together nut butter, coconut sugar, maple syrup, egg and vanilla. Stir in the oats, flour, salt, baking soda and vinegar

When well combined, gently stir in the dark chocolate chunks

Spoon the mixture into the parchment lined pan and smooth out with an offset spatula

Bake for 20 minutes or until the top is slightly golden

Place the pan on a cooling rack and let the pan cool completely, remove parchment and cut into 12 bars