01 - In a mixing bowl, cream together the softened butter and packed light brown sugar until the mixture is light and fluffy.
02 - Add the milk and vanilla extract to the butter-sugar mixture and stir until thoroughly combined.
03 - Gradually incorporate the heat-treated all-purpose flour and salt into the dough, mixing until just combined. Avoid overmixing.
04 - Gently fold the mini semisweet chocolate chips into the cookie dough until evenly distributed.
05 - Using a tablespoon, scoop portions of the cookie dough and roll them into uniform balls. Arrange the dough balls on a baking sheet lined with parchment paper.
06 - Place the baking sheet with the dough balls into the freezer for at least 30 minutes, or until they are firm to the touch.
07 - While the dough balls are chilling, melt the chopped chocolate (and optional oil) in a microwave-safe bowl. Heat in 20-second intervals, stirring between each, until the chocolate is smooth and fully melted.
08 - Using a fork, carefully dip each chilled dough ball into the melted chocolate, allowing any excess chocolate to drip back into the bowl. Return the coated truffles to the parchment-lined baking sheet.
09 - If desired, immediately sprinkle the wet chocolate coating with extra mini chocolate chips or a pinch of sea salt.
10 - Refrigerate the truffles for 15 to 20 minutes, or until the chocolate coating has completely set.