⅓cup(28g)unsweetened or Dutch-process cocoa powder (see note)
2 ⅓cups(495g)granulated sugar
½cupvegetable, canola, or avocado oil (could also try melted coconut oil)
4tablespoons(57g)salted butter, melted
2large eggs + 2 large egg yolks
1 ¾cups(249g)all-purpose flour
1cup(170g)semisweet or bittersweet chocolate chips
Preheat oven to 350 degrees F. Line a 9X13-inch metal pan with aluminum foil and lightly grease with cooking spray (the lining of the pan is optional but helps with cleanup or pulling out the whole slab of brownies).
In a large bowl, whisk together the boiling water and chopped chocolate until smooth (if the chocolate doesn't melt fully, microwave the water/chocolate mixture for 20-30 seconds). Add the cocoa powder and whisk together.
Add the sugar, oil, butter, eggs and vanilla. Mix until smooth and well-combined.
Add the flour and salt and mix until just combined and no white streaks remain. Stir in the chocolate chips (don't overmix, just fold them in until evenly distributed).
Spread the batter evenly in the prepared pan. Bake for 25-30 minutes until crackly on top and set around the sides. Cool completely (and chill, if desired - makes cutting easier and chilled brownies are just straight up divine).
Chocolate Chips: my favorite brand of unsweetened chocolate (or chocolate chips) is Ghirardelli or Guittard. If you don't have unsweetened chocolate on hand, you could try using bittersweet or semisweet chocolate and reducing the sugar a little (I haven't tried that myself, so I can't tell you the exact details - you'll have to experiment a bit). For extra chocolate flavor, I sometimes bump up the 2 ounces of unsweetened chocolate to 3 ounces (not necessary, but tasty for ultra-chocolate lovers). Eggs: I know some of you are going to be tempted to throw in three large eggs instead of using the 2 large eggs + 2 egg yolks. Just to let you know, I DID try the three egg variation, and the texture of the brownies wasn't the same, so I highly recommend following the recipe for the full fudgy effect. If it helps, egg yolks contribute to moisture in baking while egg whites help with structure (but can sometimes dry out baked goods). Cocoa Powder: I have made these brownies with both Dutch-process and natural, unsweetened cocoa powder. Both work great. The Dutch-process lends a richer, milder, darker, and slightly sweeter flavor. Most often I use natural, unsweetened because I always have it on hand and it's usually cheaper (which is important when you make these brownies as much as we do!).