Preheat your oven to 350°F (175°C). This is crucial for ensuring that your brownies bake evenly.
Line a 9x13-inch baking pan with parchment paper, leaving some overhang to make lifting the brownies out easier later. This will also help prevent sticking.
In a saucepan over medium heat, melt the unsalted butter along with 1 cup of the semi-sweet chocolate chips, stirring until smooth. Once melted, remove from heat and stir in the water or coffee.
In a large mixing bowl, whisk together the melted chocolate mixture with sugar, eggs, and vanilla extract until well combined.
In another bowl, sift together the all-purpose flour, baking soda, and salt. Gradually add the dry ingredients to the wet ingredients, stirring until just combined. Be careful not to overmix!
Gently fold in the remaining 12 ounces of semi-sweet chocolate chips, ensuring they are evenly distributed throughout the batter.
Pour the brownie batter into the prepared baking pan and spread it evenly. Bake in the preheated oven for 25-30 minutes or until a toothpick inserted in the center comes out with a few moist crumbs.
Allow the brownies to cool in the pan for at least 10-15 minutes before lifting them out using the parchment paper. Cut into squares and serve warm or at room temperature. Enjoy the ooey-gooey goodness of your Boyfriend Brownies!