Preheat your oven to 350°F (175°C) and line your 9x13 inch baking pan with parchment paper, leaving some overhang for easy removal.
In a medium saucepan over low heat, melt the 1 cup unsalted butter and 1 cup of water or coffee. Once melted, stir in 1 ½ bags of semi-sweet chocolate chips until smooth and glossy.
Remove the saucepan from heat and let it cool slightly. In a large mixing bowl, whisk together the melted chocolate mixture, 4 large eggs, and 1 to 2 teaspoons of vanilla extract until well combined.
In another bowl, sift together 1 cup all-purpose flour, 1 teaspoon baking soda, and 1 teaspoon salt. Gradually fold the dry ingredients into the wet mixture until just combined. Be careful not to overmix!
Gently fold in the remaining ½ bag of semi-sweet chocolate chips for extra melty goodness.
Pour the brownie batter into the prepared baking pan, spreading it evenly. Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs.
Allow the brownies to cool in the pan for about 15 minutes before lifting them out using the parchment paper. Cut into squares and serve.
