6ozsdark chocolate bars the ones I used are 3 ozs each, I use 2 bars
Leave butter at room temperature about half an hour before your start making the brownies. Or soften the butter in microwave right before.
Pre-heat oven to 350 degrees F. Whisk the eggs until creamy. Add sugar and brown coconut sugar. Whisk until well incorporated.
Add vanilla extract and avocado oil, whisk to mix together. Then add butter. Continue mixing.
Add flour and cocoa on the bowl, at this point mix slowly as especially cocoa can splash and create dust everywhere. You don't need to sift unless cocoa has clumped together. Mix until everything is incorporated into a creamy, chocolate cream. At this point you can switch from a whisk to a spatula if you feel more comfortable mixing with a spatula. You'll be able to scrape flour from the bottom of the bowl much easier with a spatula.
Add chopped walnuts and chocolate chips, mix very little just to incorporate. Don't overdo the mixing at this point.
Cut the chocolate bars into pieces. While trying to cut with a knife, the bars will crumble in small pieces.
Pour the batter into a baking dish (9 by 9 inches). Use parchment paper to help remove the baked brownies easier. If you don't have parchment paper, grease the dish lightly before pouring batter in it. Add the crumbles of the chocolate bars over the batter, spread evenly.
Place baking dish into the middle rack of the pre-heated oven. I have to bake my brownies for about 24 minutes. However, please check with a toothpick around 22 minutes and be mindful for every minute you let them bake after that. Each oven is slightly different so the baking time might vary anywhere from 22 to 26 minutes in my experience based on the ovens I have had a chance to use.
Once baked, get the dish out of the oven and let cool for at least 30 minutes. Try to resist cutting into the brownies too soon.
Cut brownies in 9 squares (3 by 3). This will make for very generous servings! Enjoy:)
I cut the brownies in 9 square slices, they were big generous slices. I think you can cut them even smaller. My kids for example share one slice as they can't finish one whole square on their own.