Master the Art of Crafting

Master the Art of Crafting Perfect Brownies!
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INGREDIENTS  
2 ½ sticks unsalted butter plus more softened for greasing
8 oz goodquality semisweet chocolate 225 g or bittersweet chocolate 6070 cacao roughly chopped
¾ cup unsweetened dutch process cocoa powder 90 g divided
1 tablespoon espresso powder
2 cups granulated sugar 400 g

½ cup dark brown sugar 110 g packed
2 teaspoons vanilla extract
2 teaspoons kosher salt
6 large eggs
1 cup allpurpose flour 125 g
flaky sea salt for sprinkling
PREPARATION 
Step 1 Grease a 9x13inch 23x33cm dark metal pan with softened butter then line with parchment paper leaving overhang on all sides. Grease the parchment with softened butter. 
Step 2 Combine the chopped chocolate ¼ cup 30 g of cocoa powder and espresso powder in a heatproof liquid measuring cup or medium bowl and set aside. 

Step 3 Add the butter to a small saucepan over medium heat and cook until the butter just comes to a vigorous simmer about 5 minutes swirling the pan occasionally. Immediately pour the hot butter over the chocolate mixture and let sit for 2 minutes. Whisk until the chocolate is completely smooth and melted then set aside. 
Step 4 Combine the granulated sugar brown sugar vanilla extract salt and eggs in a large bowl. Beat with an electric hand mixer on high speed until light and fluffy about 10 minutes. It will be similar to the texture of very thick pancake batter. 

Step 5 With the mixer on pour in the slightly cooled chocolate and butter mixture and blend until smooth. 
Step 6 Position a
rack in the middle of the oven and preheat to 350F 180C. 
Step 7 Sift in the flour and remaining cocoa powder and use a rubber spatula to gently fold until just combined. 
Step 8 Pour the batter into the prepared baking pan and smooth the top with a spatula. Bake until lightly puffed on top about 20 minutes. 
Step 9 Remove the baking pan from the oven using oven mitts or kitchen towels then lightly drop the pan on a flat surface 12 times until the brownies deflate slightly. Sprinkle with flaky sea salt. 
Step