Preheat the oven to 350°F. Grease and line an 8X8-inch with parchment paper. Set it aside.
Prepare a double boiler and melt the chocolate and butter until smooth and shiny. See notes.
6 Ounce Dark chocolate, ⅓ cup+1 tablespoon Butter
Use a hand mixer or stand mixer set on the paddle attachment. Beat the eggs and both sugars. Beat this mixture for 3-4 minutes until it is light and pale in color.
2 Eggs, ¾ cup Granulated sugar, ¼ cup Brown sugar
Add the vanilla extract and mix.
2 teaspoon Vanilla extract
Mix in the chocolate mixture and mix.
Sift the flour and cocoa powder, then add them to the batter. Use a spatula to fold the dry ingredients into the mixture. Do not overmix.
1½ tablespoon Cocoa powder, ½ cup All-purpose flour
Pour the batter into the lined pan, and smooth out the top. Bake it for 20-25 minutes. Bake it for 20-25 minutes. Let the brownie cool down for at least 2 hours before
Notes
Prepare the double boiler. Pour half a cup of water into a small saucepan and bring it to a boil. Let the water simmer on low heat.
Place the chocolate chunks and butter in a bowl on top of the simmering water, and ensure the simmering water is not touching the bottom of the bowl. Stir occasionally until the butter and chocolate are melted and smooth.