In a medium sauce pan over high heat, boil the sweet potato pieces for 8-10 minutes or until very tender, drain and rinse with cold water.
Position a rack in the center of the oven, and preheat to 350° Fahrenheit. Use a non-stick 8" x 8" baking pan or line with parchment paper.
To soften the dates, place them in a small dish with 1 tablespoon of water in the microwave and heat on high for 30 seconds.
To a large food processor, add the dates (and liquid), cooled sweet potato pieces, oats, cocoa powder, applesauce, peanut butter, coconut sugar, vanilla extract, baking powder and salt. Blend well until completely mixed, for about 2 minutes, stopping to scrape down sides as needed. You want a creamy mixture, with no chewy chunks of oats.
Stir in the chocolate chips, but DO NOT BLEND. (I remove the blade and stir them in right in the food processor.)
Spread the brownie mixture evenly in the pan with a rubber scraper or the back of a large spoon. Optional: Top with the extra chocolate chunks and crushed peanuts if using.
Bake uncovered, 18-22 minutes, or until a toothpick placed in the center comes out clean. (If the toothpick hits a chocolate chip, it will come out coated with melted chocolate! Check a different spot.)
Allow the brownies to cool before cutting. If they're still a bit soft after cooling, you can place them in the fridge to firm up. I recommend storing them at room temperature.
If you can't find vegan chocolate chunks, you can break up a vegan chocolate bar.