Place the crushed shortbread cookies in a large mixing bowl.
Add the softened cream cheese to the cookie crumbs.
Mix thoroughly with a spoon or your hands until a smooth, uniform dough forms.
Roll the mixture into 24 small, even-sized balls and place them on a parchment-lined baking sheet.
Refrigerate the balls for 10 minutes to firm up.
In a microwave-safe bowl, combine the chopped semi-sweet chocolate and vegetable oil.
Microwave in 30-second intervals, stirring after each, until the chocolate is fully melted and smooth.
Using a fork or dipping tool, dip each cookie ball into the melted chocolate, ensuring it is fully coated.
Place the coated truffles back onto the parchment-lined baking sheet.
Refrigerate the truffles for at least 30 minutes or until the chocolate has set.
Serve chilled or at room temperature.