Step 1
Cream sugar and butter together with a spatula until light and creamy. Set aside.
Step 2
Heat an inch of water in a pot set over low heat. Melt dark chocolate in a heat-proof bowl placed over the pot. Stir with a small spatula.
Step 3
Place chestnuts in a food processor; pulse on and off until very finely ground. Add chestnuts to the sugar-butter mixture and stir until combined. Add salt cayenne pepper vanilla extract and brandy. Stir well. Pour in the melted chocolate and mix again until filling is well blended.
Step 4
Scoop filling onto a silicone-lined baking sheet and smooth out if necessary. Cover the balls in plastic wrap and refrigerate while you prepare the white chocolate coating.
Step 5
Reserve about 20% of the white chocolate to stir in later. Melt the rest in a heat-proof bowl over a pot of simmering water until an instant-read thermometer inserted in to the chocolate reads 105 degree F (41 degrees C). Add the reserved white chocolate and stir until melted.
Step 6
Place 1 chocolate truffle on a fork and hold it up above the white chocolate coating. Spoon on the white chocolate until ball is well coated. Use another fork to push the truffle onto a lined baking sheet. Repeat with the remaining truffles and coating. Place the bowl of coating back over hot water if it chocolate starts to harden.
Step 7
Mix confectioners' sugar with enough milk to make a very thick paste that will hold together well. Dye it pink with red food coloring. Transfer into a piping bag and pipe a small dot on top of each truffle. Serve truffles in paper candy cups.