Preheat the oven to 325 degrees F. Prepare a 9 by 13 inch baking dish by spraying with non-stick cooking spray and then lining with parchment paper (or foil, but then spray the foil with cooking spray as well). Set aside.

In a large mixing bowl, combine the oats, flour, brown sugar, flax meal, baking soda, and salt.

Combine the ½ cup coconut oil and peanut butter in a small bowl. Microwave for 30 seconds or so, just to melt it when you stir to combine. Stir in the maple syrup and vanilla. Pour into the dry mixture and stir well to fully combine. Add the mini chocolate chips and chopped nuts. Stir once more.

In a small bowl, add the dark chocolate chips and ½ tablespoon coconut oil. Place in the microwave and heat in 30 second increments, stirring in between, until melted. Use a spatula to spread the chocolate in the prepared pan, bringing the chocolate up the sides about ½ inch or so.

Press the oatmeal mixture into the pan, making sure to be firm doing so. Bake in the preheated oven for 18-20 minutes. Be sure to cut into the bars as soon as they come out of the oven. I like to do this with a bench scraper (like this one!). Allow to cool and then cut into bars once more.

The parchment paper allows you to pull all the bars out of the pan. This will help prevent them from breaking apart. Store at room temperature in an airtight container.