Preheat oven to 325F. Grease and flour or line a 9x13-inch baking dish with parchment paper. Set aside.
Add butter, sugars, and water to a large saucepan.
Bring to a boil over medium-low heat, stirring constantly.
Remove from heat.
Stir in 1 ¾ cups chocolate chips until melted and combined.
Let cool for 5 minutes.
Whisk in the eggs one at a time, whisking the entire time so you don't get egg pieces in the brownies.
Whisk in the vanilla.
Add the flour, baking soda, cinnamon, cayenne pepper, and salt. Whisk in just until combined.
Stir in remaining chocolate chips.
Pour the batter into the prepared pan.
Bake for 35-50 minutes, or until a wooden toothpick inserted in the center comes out with a few fudgy crumbs. You don't want the toothpick to be clean or the brownies will be overcooked.
Cool to room temperature in the pan on a wire cooling rack.
Cut and serve.
Butter: I use salted butter in this recipe.
Chocolate chips: If you like sweeter brownies, use semisweet chocolate chips in place of the bittersweet.
Flour: Be sure to use a light touch and properly measure the flour. To measure the flour, sift or stir the flour, lightly spoon into the measuring cup, and level. If you use too much flour, you'll end up with cakier brownies.
Cayenne pepper: You can use an equal amount of chili powder in place of the cayenne pepper. You can also increase the cayenne pepper if you want more spice.
Baking: It's important to slightly underbake brownies to keep them moist and fudgy. This is why it's important to quit baking the brownies when the toothpick comes out with a few fudgy crumbs.