While my sister very much enjoyed her spicy brownies, and reading all of your comments last night, there's still no baby. I think her putting hot sauce on everything has made the kid immune. So we're still waiting on that, but I'll keep you posted ;)
Now...about the recipe. I guess I just like you guys all so much that I'm willing to spill my top secret secrets to you, lucky ducks! (A top secret secret that I found by googling "spicy Mexican brownies," and clicking on the first of many links.) And the secret is this: prepare your most tried and true brownie recipe, or box mix, (I'm rather partial to this) and add 3/4 tsp chipotle powder and 1 tsp cinnamon. These bad boys are hot stuff, lemme tell you! You'll probably be wanting to wash them down with a margarita or two.
Go forth and bake, my lovelies! I'd love to hear how they turn out!