Has anyone tried these with some chili powder or cayenne and if so how much would you use?

Thanks you guys! I really appreciate it!I love a little spice in my brownies and other chocolate stuff. :) Although, I made these after I posted the question and these were wonderful!!!

I like to add chipotle powder and cinnamon to brownies. For this recipe, maybe 1/2-3/4 tsp chipotle and 1/4-1/2 tsp cinnamon?

genny, yes and yes. i have also used espresso powder and medium coarsely ground black pepper. Measurements of cayenne/chili powder? 1/2 tsp ,mix,taste; repeat til you like it.I let the batter ripen for a day on the counter, taste and adjust before putting in the pan and baking.

Just in case anyone else was curious about this, I wanted to share that Jillian Bernardini weighed in on this question over in the recipe comments and said: "When I used about a teaspoon and a half for Dorie Greenspan's cocoa shortbread cookies, I could taste the aftermath of the heat. in a good way though!"