Preheat the oven to 350°F (175°C).
Melt the butter and chocolate in a saucepan.
Remove from heat and whisk the sugar into the melted mixture.
Add the eggs and vanilla extract, mixing until fully blended.
Sift together the flour, cocoa powder, and salt in a separate bowl.
Fold the dry ingredients into the wet mixture until just combined.
Pour the batter into a greased 8x8-inch baking pan.
Bake for 25-30 minutes or until a toothpick comes out mostly clean.
Allow the brownies to cool completely in the pan.
Cut the brownies into small cubes.
Shape the cubes into balls using your hands.
Melt the chocolate for coating in a microwave-safe bowl.
Dip each truffle into the melted chocolate and allow excess to drip off.
Sprinkle with chocolate sprinkles, if desired, and set on parchment paper.
Refrigerate the truffles until the coating is firm.