Preheat oven to 350 degrees. Line the inside of an 8-inch (I used my 8-inch glass baking dish) or 9-inch square baking pan with 2 lengths of foil or parchment paper, positioning the sheets perpendicular to each other and allowing the excess to extend beyond the edges of the pan. Then lightly butter the foil or parchment paper. I always butter the bottom piece so that the top piece sticks to it.
Chop up and measure out your dark chocolate. I love using these Ghirardelli bars because they are each 4oz (8oz total) so I do not have to measure anything.
These bars are also thin enough to break apart with my hand so I don’t have to actually chop them up with a knife. I break them apart in little pieces right over the heatproof bowl that I’m going to melt the butter and chocolate in (I do this before I set the bowl over the simmering water). It saves me a cutting board and knife to clean up. If you don’t have thin chocolate bars like these, then chop up your chocolate using a serrated knife.
Tip: I always place some parchment paper on top of my cutting board when chopping up chocolate as it helps make clean up easier and you can always just lift and pour those small pieces of chocolate into your pan. It's easiest to chop chocolate with a serrated knife.
Placed the chopped chocolate and butter into a heatproof bowl. Set the bowl over a pan of simmering water, (make sure that the bowl doesn’t touch the water) and melt the butter and chocolate together, stirring constantly with a rubber spatula, until melted and smooth.
Immediately remove the chocolate from the heat and pour the chocolate mixture into a large bowl (unless the bowl you're using to melt the chocolate in is large enough). Make sure you use a spatula here so you can get all the chocolate goodness into the bowl.
Add the 3/4 cup sugar and the 1 teaspoon vanilla to the melted chocolate and mix until combined.
Using a whisk, add in the eggs 1 at a time until combined.
Add the flour and stir the batter energetically for 1 minute until the batter loses it graininess, becomes smooth and glossy, and pulls away a bit from the sides of the bowl. The batter will also lighten up a bit in color.
Note: This is a very important step!! Make sure that your stir vigorously for 1 full minute or a bit more. I suggest timing yourself. By doing this step you will end up with a batter that's rich, thick, satiny smooth, and glossy as can be and brownies that are rich and fudge-like. I'm going to warn you that you are going to have one tired arm after stirring vigorously for a minute, believe me!
Using a spatula, gently fold in your chocolate chips.
Scrape the batter into the prepared pan using a spatula to make it even.Bake until the center feels almost set and the edges are a bit firm, about 30-35 minutes. In my oven, my brownies are done around 32-33 minutes. Do not over bake.
Note: Ovens vary in temperature and baking times, so get to know your oven and know how long it takes to bake things. If your oven tends to cook things faster, then check it before 30 minutes etc.
The first time I baked these, I honestly thought they were underdone, but that is the way they are supposed to be. They're truly more of a fudge-like brownie than cake-like one. They will also firm up as they sit and cool.
Let the brownies cool completely in the pan (about an hour or so) before lifting the foil or parchment paper and the block of brownies out of the pan.
Peel down the parchment paper and cut the brownies into squares and store them in a sealed container.