Preheat the oven to 350°F (175°C).
Melt the unsalted butter and chocolate chips together.
In a large bowl, whisk together the granulated sugar, brown sugar, and eggs until smooth.
Stir in the vanilla extract followed by the melted chocolate mixture.
Sift the flour, cocoa powder, and salt together before folding into the mixture.
Add in the chocolate chips and mix gently to combine.
Transfer the brownie batter to a greased 9x13 inch baking pan.
Bake for 25-30 minutes or until a toothpick inserted comes out with a few moist crumbs.
Let brownies cool before cutting into small squares and rolling into balls.
Melt the dark chocolate in a heatproof bowl over simmering water or in short bursts in the microwave.
Dip each brownie ball into the melted chocolate, letting excess drip off before placing on a waxed paper lined baking sheet.
Chill the truffles in the refrigerator until the chocolate coating is set.