Description
Don't be fooled by the length of the recipe instructions. For ease, this cake comes together best when a couple components are quickly assembled ahead of time. As such, making the batter itself is a breeze! And smells ah-mazing while baking!!
Ingredients
Scale
For the cake:
- 1 1/2 sticks unsalted butter (12 TB, 6 oz)
- 1 1/2 cups granulated sugar (300 g)
- 3 eggs, separated
- 1 TB pure vanilla extract
- 2 cups full-fat sour cream, room temperature (16 oz)
- 3 cups cake flour (360 g)
- 1 1/2 tsp baking powder
- 1 1/2 tsp baking soda
- 1 1/2 tsp fine-grain salt (like table or sea salt)
- 1 bag mini chocolate chips, divided (10 oz)
- powdered sugar, for dusting
For the streusel topping:
- 1/2 cup packed light brown sugar (106 g)
- 1/4 tsp fine-grain salt (like table or sea salt)
- 4 TB unsalted butter, melted (1/4 cup, 2 oz)
- 1/2 cup all-purpose flour (60 g)
Instructions
- Preheat oven to 350 degrees.
- Butter a 9x13-inch metal baking pan and line the bottom with parchment. I like to leave an overhang on two sides for easier removal.
- Brown the butter: Melt the butter in a medium sauté pan over medium heat. Gently swirl the pan every few seconds until the butter starts to smell nutty and brown bits appear on the bottom (~5 minutes). Immediately pour the butter into a heatproof bowl, scraping up all those delicious brown bits, and then let cool for ~10 minutes.
- Meanwhile, make the streusel topping: In a small bowl, combine the brown sugar and salt, then stir in the melted butter. Stir in the flour just until crumbly. Don't over mix (you want crumbs, not a paste). Set aside.
- Measure out 1/4 cup mini chocolate chips and then set aside for topping the cake.
- In a large bowl, whisk together the cake flour, baking powder, baking soda, and salt. Set aside.
- In the bowl of a stand mixer fitted with the whisk attachment, beat the egg whites until stiff peaks form. Pour into a clean, separate bowl and set aside.
- In the bowl used to beat the egg whites, but now fitted with the paddle attachment, beat the brown butter and granulated sugar on medium speed until combined. Add in the egg yolks, and then the vanilla, and beat until the mixture appears cohesive and smooth. Scrape down the sides of the bowl as necessary.
- With the mixer on low, alternately mix in the sour cream and flour mixture (half of each at a time) until the batter is just combined, scraping down the sides of the bowl as necessary.
- Remove the bowl from the stand mixer and gently fold in the egg whites with a rubber spatula. Then, fold in the mini chocolate chips (less the reserved 1/4 cup).
- Pour the batter into the prepared pan, smoothing the top. Top with the streusel, and then sprinkle over the reserved 1/4 cup mini chocolate chips.
- Bake for 35 minutes, or until a toothpick inserted in the middle comes out clean. Let cool in pan on a wire rack. Dust with powdered sugar before serving, if desired.
Notes
- Be sure the brown butter has cooled slightly before using. If it's too hot, it will dissolve the granulated sugar.
- If you'd prefer a more in-depth tutorial on browning butter, this is a great resource from Serious Eats.
- Tip: It's easiest to separate eggs when their cold. But the whites will whip up best when at room temperature. I like to separate the eggs as far in advance as possible. If more than an hour, I'll cover the two bowls with saran wrap - this especially helps the yolks from drying out. A bit excessive, but a habit from my pastry chef-ing days.
- Be sure the beaters/whisk attachment used to whip the egg whites are fully clean - any residual fats/oils will hinder the whites' whipping potential.
- To save on dishes, beat the egg whites first, in the same stand mixer bowl you'll use to make the batter. Or, just before folding into the batter, whip the egg whites in a separate bowl with a hand mixer (or if you're lucky enough to have two bowls for your stand mixer!).
- The streusel topping is optional, but definitely brings this coffee cake to another level in both texture and flavor. Alternatively, simply sprinkle 2 TB granulated sugar on top of the cake before baking.