Could the popular 100-hour brownies possibly be worth the wait? We tested the recipe alongside a regular batch to find out.
100-Hour Brownies
Updated on Oct. 11, 2021
When you crave something chocolaty and comforting, it’s hard to think of anything better than a quick batch of brownies. Well, what if the recipe took days to make? Could even 100-hour brownies be worth the wait?
This question was on everyone’s mind after Alvin Zhou, a producer for BuzzFeed’s Tasty videos, shared “100-Hour Fudgy Brownies” on his YouTube channel. The video shows Alvin steadily moving through the steps to make his brownies, like browning butter, whipping eggs and chopping chocolate before stashing his brownies away for an excruciatingly long wait.
Fans of this 100-hour brownie recipe have spoken, saying that they’re the best brownies ever—and we had to find out for ourselves.
How to Make 100-Hour Brownies
Ingredients
Butter mixture:
- 1 cup (2 sticks) unsalted butter
- 1 tablespoon espresso powder
- 1 coffee ice cube
Batter mixture:
- 4 large eggs
- 1 tablespoon vanilla paste or extract
- 2-1/4 cups granulated sugar
- 1/2 cup Dutch-processed cocoa powder
- 1 tablespoon espresso powder
- 1 tablespoon kosher salt
- 8 ounces 75% cacao chocolate, melted
- 1-1/2 cups all-purpose flour
Chopped chocolate:
- 3-1/2 ounces chopped milk chocolate
- 3-1/2 ounces chopped 75% cacao chocolate
- 6 ounces chopped 75% cacao chocolate for the topping
Editor’s Tip: Since this recipe calls for a specific type of cocoa powder, make sure you know the difference between natural and Dutch-processed cocoa powders.
Making the Brownie Batter
Alvin Zhou’s recipe begins by browning the butter to give it a deeper color and flavor. Don’t skip this step because it adds so much to the brownie experience. (Follow this guide to learn how to brown butter if it’s your first time.) Espresso powder is then stirred into the browned butter to bloom the flavor, along with a coffee ice cube to cool the mixture afterward.
While the butter cools, eggs and sugar are whipped until light before adding the cocoa powder, salt, flour, melted chocolate and more espresso powder. The espresso-butter mixture is then stirred together to create a ridiculously rich batter.
Fold in the chopped dark and milk chocolate pieces, then spoon the batter into a pan (13×9-in. for thin brownies or an 8-in. square pan for thicker slabs). The final step is to sprinkle more chopped dark chocolate over the top.
The First Wait
Here’s the hard part: You have to wrap that pan and put it in the fridge for three days.
You read that right. These brownies get chilled for 72 hours. If you’re like me, your first question is, why do we have to wait so long? I asked the Taste Of Home Test Kitchen experts to weigh in.
The long chill will allow the flavors more time to “marinate together,” says senior food stylist Shannon Norris. She adds that having a cold batter will also prevent it from over-baking.
Deputy culinary editor James Schend told me that the long rest will also let the flour fully hydrate, giving the batter a deeper color and creating dense and moist brownies.
Bake, Then Wait Again
After three days in the refrigerator, it’s time to bake. The brownies go straight into a 350°F oven to bake for 30 minutes (or 45 minutes if you’re making thicker brownies in a square pan.) When you pull the pan from the oven, the brownies will be wobbly in the center, which is how you’ll know they’re going to be fudgy.
And then comes another long wait. Cover the top of the pan in foil, and pop the hot pan into the freezer for 30 minutes. Alvin Zhou says he learned this trick from a pastry chef to help keep moisture in the brownies. After 30 minutes, the brownies go back into the fridge for 24 hours to cool all the way through and set the texture.
The Final Result
All that waiting was really hard, but you know what? The brownies were absolutely incredible.
To really understand the difference, we made two batches of this recipe: the 100-hour version and one baked right after mixing. When you put the sliced brownies from each batch side by side, you can easily see the difference. The normal brownies have the cakier crumb texture you expect, and because the top sank as the brownies cooled, they were chewy, too.
But the 100-hour brownies? As our Test Kitchen experts predicted, these brownies were fudgy with a texture that was so soft and smooth that it was almost mousse-like.
The flavor was so deep, buttery and chocolaty—it was exquisite. The chunks of milk and dark chocolate inside were lovely to sink our teeth into. We also noticed that the dark chocolate in the normal batch retained its bitterness, but in the 100-hour brownies, the bitterness was gone.
Are 100-hour brownies worth it?
Even for such ridiculously delicious brownies, four days of prep isn’t always an option. But for special occasions? Yes, we would absolutely make 100-hour brownies again! They’re one of those dessert experiences that people will love to say they’ve been a part of.
This recipe teaches us some techniques worth remembering for a flavor that excels, even when making normal brownie recipes. Using nutty and fragrant browned butter, adding coffee or espresso powder, and adding a blend of milk and dark chocolate result in a more flavorful batch. Resting the batter before baking will let flavors meld and deepen, even if it can’t be a full 72 hours. And, chilling the brownies after baking will help with that fudginess.
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