Preheat your oven to 350°F (175°C).
Line an 8x8 inch baking pan with parchment paper, leaving some overhang.
In a medium saucepan over low heat, combine the cubed unsalted butter and finely chopped unsweetened chocolate. Stir continuously until melted and smooth. Remove from heat and let it cool slightly.
Add the sugar and a pinch of salt to the melted chocolate mixture. Stir until well combined and glossy.
Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract until the batter is smooth.
Gently fold in the cake flour until just combined, being careful not to overmix. Finally, fold in the chocolate chips.
Pour the brownie batter into the prepared baking pan, spreading it evenly. Bake for about 20-25 minutes, or until a toothpick inserted comes out with a few moist crumbs.
Once baked, let the brownies cool in the pan for about 10 minutes. Use the parchment paper overhang to lift them out onto a wire rack to cool completely before cutting into squares.
