01 - In a large bowl, cream together softened butter, light brown sugar, and granulated sugar until light and fluffy.
02 - Add milk and vanilla extract to the creamed mixture and mix until well combined.
03 - Stir in heat-treated all-purpose flour and salt until just incorporated.
04 - Gently fold mini semi-sweet chocolate chips into the dough.
05 - Scoop tablespoon-sized portions of dough and roll into balls; place on a parchment-lined tray.
06 - Freeze the dough balls for 20 minutes until firm.
07 - Melt chopped chocolate and optional vegetable oil in microwave-safe bowl in 30-second intervals, stirring after each, until smooth.
08 - Using a fork or dipping tool, dip each dough ball into melted chocolate, letting excess drip off.
09 - Place coated truffles back on tray; optionally sprinkle with extra mini chips or sea salt before chocolate sets.
10 - Refrigerate truffles for 15 minutes until chocolate coating is firm; serve chilled or at room temperature.