Preheat oven to 350 F.

Grease and line an 8 x 8 inch square baking pan with parchment paper, leaving a bit to overhang on two sides so you can easily lift out the brownies.

In a small sauce pot, bring about 1 inch of water to a simmer.

Place a large bowl (metal) on top of the sauce pan. Add the dark chocolate and butter stirring frequently over low heat.

Remove the butter-chocolate mixture from the heat. Whisk in eggs, sugar, and vanilla into the melted chocolate until very smooth.

Add the dry ingredients (flour and salt) to the wet ingredients, and stir to combine.

Scrape the brownie batter into prepared square pan and spread evenly.

Bake until puffed and just barely set, 40 to 50 minutes.

When done, brownies will be slightly domed with a crinkly top and they will feel set, not liquidly when gently tapped with your finger. The batter will still be gooey should you stick a toothpick inside, resulting in fudgy middles when you cut the brownies open.

Let the brownies cool in the pan to room temperature.

Once cool, lift the brownies out of the pan using the parchment paper, and cut into 9 or 16 squares to serve. This is a very rich brownie, so small pieces work just fine.

Leftover brownies keep very well in an airtight container for several days.