100-Hour Brownies

I consider myself quite a brownie connoisseur — I have loved brownies since I was a child when my mom would take me to the mall to go shopping on the weekend. As a treat, she would buy me one of the Mrs. Fields Double Fudge Brownies, and I would cherish that thing for days, pinching little pieces off and rolling them into little balls to eat one at a time.  So me and brownies go way back. 

Given this obvious expertise in brownie eating, I was very curious to see if Alvin Zhou’s  100-hour brownie was really worth it. I mean, who wants to wait four whole stinkin’ days for a brownie, especially when you have kids!

So what I did was I made this recipe and baked a portion of it right away in order to see the difference from the second batch which I allowed to rest following Alvin’s directions. 

Essentially what you will be doing, and what I did, is making a brownie batter which you will let rest for a period of three days; after that you will bake it; and then you will let it rest for another twenty-four hours to allow the flavors to develop.

A square of brownie on a gray plate.

100-Hour Chocolate Brownie

This batch of brownies takes 100 hours to make. Can you wait that long?
4.15 from 7 votes
Prep Time 1 hr
Cook Time 45 mins
Resting Time 4 d
Total Time 4 d 1 hr 45 mins
Course Dessert
Servings 24
Calories 314924 kcal


  • hand mixer
  • 9" brownie pan
  • freezer
  • oven
  • refrigerator


Browned butter

  • 1 C. butter 2 sticks
  • 1 T. espresso powder
  • 2 T. coffee ice cubes


  • 4 eggs
  • 1 T. vanilla paste You can substitute the same amount of vanilla extract.
  • C. sugar
  • 1/2 C. cocoa powder
  • C. all-purpose flour
  • 2 tsp. Kosher salt 
  • 1 tbsp. espresso powder
  • 8 oz. 75% dark chocolate, melted Cooled to room temperature.
  • oz. milk chocolate, chopped
  • oz. 75% dark chocolate, chopped


  • 6 oz. 75% dark chocolate, chopped


  • In a nonstick sauce pan, melt butter on medium/ow heat until golden. Be careful not to burn the butter.
  • Once the butter is golden, turn off the heat and add espresso powder. Add coffee ice cubes; melt completely, allowing the brown butter to cool
  • In a large bowl, add eggs, vanilla paste, and sugar; and beat with a hand mixer on medium/low speed until light and fluffy. The batter should form a ribbon.
  • Sift in cocoa powder, espresso, and salt.
  • Use a spatula to stir in the browned butter mixture.
  • Next add the melted chocolate; and sift in the flour, folding gently.
  • Add the two types of chopped chocolate.
  • Line a 9” x 13” pan with parchment paper. Add the batter into the prepared pan and top with the chopped dark chocolate shards.
  • Wrap the pan in plastic wrap and place in the refrigerator to rest for 72 hours.
  • Preheat oven to 350°.
  • Bake batter for 30 minutes.
  • Remove the brownies from the oven and wrap tightly with aluminum foil. Place in the freezer for 30 minutes.
  • Remove brownies from the freezer and refrigerate for 24 hours before serving.




Calories: 314924kcalCarbohydrates: 56456gProtein: 5189gFat: 245gSaturated Fat: 95gTrans Fat: 1gCholesterol: 49mgSodium: 17330mgPotassium: 1514035mgFiber: 5gSugar: 25020gVitamin A: 294IUCalcium: 60449mgIron: 1850mg
Keyword brownies, Chocolate, dessert, fudgy
Tried this recipe?Let us know how it was!

Is It Worth 100 Hours?

So, is it worth waiting a hundred hours for a brownie? Did this four day process improve the flavor of the brownies enough to warrant such an excruciating wait? Nah. This tested this recipe with out the 72-hour resting period and I found it too bitter for my tastes. I had hoped that the 72-hour resting period would mellow out the bitter dark chocolate and coffee flavors, but it was still too bitter. The brownies were beautiful though, but in my opinion not worth the 100 hour wait. I you still want brownies why not try these tasty mochi brownies.

An unbaked batch of brownies topped with shards of dark chocolate.

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