Blend all ingredients (except chocolate chips and walnuts; and only add 1/2 Tbsp orange zest at this time) in a food processor for about a minute until batter is a smooth consistency. You may need to stop the food processor once and scrape down the sides.
Once the batter is one consistency (it will be very thick, like cookie dough), remove the blade.
Spread half the batter into a greased square pan.
Top with 1/4 cup chocolate chips, then spread the second half of the batter on top.
Sprinkle with 2 tsp orange zest. Bake at 350 degrees for 30 minutes.
About 5 minutes before the bars are done, melt the remaining 1/2 cup chocolate chips in the microwave.
Remove the bars from the oven and immediately poor the melted chocolate over the top.
Spread it to cover the bars. Top with crushed walnuts and remaining orange zest.
Let the bars cool in the pan on a wire rack.
Once they are cooled completely, cut them and store in an airtight container for up to 3 days... that is if there's any left!
*Note on texture: These are a very dense bar, and thus VERY filling! A little goes a long way!
*If you need gluten free, add 4 1/2 cups gluten free oats to a blender and pulse until ground. Then follow instructions above...The nutrition facts presented here are estimates only. The brands you use and product types chosen can change the nutritional information presented. To obtain the most accurate nutritional information, you should calculate the nutritional information with the actual ingredients you use.