1. Preheat oven to 350°F. Line t3 baking sheets with parchment paper.
2. In a medium, microwave-safe bowl melt together 1 cup (180 g) of chocolate chips and the butter. Allow to cool to room temperature.
3. In a small bowl, whisk together flour, baking powder, salt and chili powder and set aside. In the bowl of a stand mixer fitted with the whisk attachment, mix together the eggs, granulated sugar, brown sugar and bitters. Continue whisking on high speed until mixture is slightly thickened and light in color, approximately 2 minutes.
4. Add cooled chocolate mixture mixing on low speed until combined. Add dry ingredients and mix on low until flour is just incorporated, scraping down sides and bottom of bowl with a rubber spatula.
5. Remove bowl from mixer and fold in remaining 2 cups (360 g) of chocolate chips and walnuts. Cover bowl with plastic wrap, and refrigerate batter for 30 minutes.
6. Using a 1 ⅓-ounce (38 g) cookie scoop (red handled) drop batter onto the prepared baking sheets, 6 cookies per sheet as cookies will spread during baking. Bake for 10 to 11 minutes. The edges of the cookies will be set and the top of the cookies will still look slightly wet. Cool completely before removing from baking sheets.