In a large mixing bowl, combine the crushed shortbread cookies and softened cream cheese.
Mix thoroughly until a smooth, uniform dough forms.
Using your hands or a small cookie scoop, form the mixture into 24 equal-sized balls.
Place the balls on a baking sheet lined with parchment paper and refrigerate for 10 minutes to firm up.
In a microwave-safe bowl, combine the semi-sweet chocolate chips and vegetable oil.
Microwave in 30-second intervals, stirring after each, until the chocolate is completely melted and smooth.
Remove the cookie balls from the refrigerator.
Using a fork or dipping tool, dip each ball into the melted chocolate to coat completely.
Allow excess chocolate to drip off, then place the coated truffles back onto the parchment-lined baking sheet.
Refrigerate the truffles for at least 15 minutes or until the chocolate coating is set.
Serve chilled or at room temperature.