Prepare your cake according to package instructions, then cut any hard edges off the cake and discard (or save for snacking).
Break up the remaining cake with a fork or your hands, and reserve ½ cup of cake crumbs for later on.
Add the remaining cake crumbs into a mixing bowl along with the softened cream cheese. Using an electric mixer, mix until the cream cheese is fully incorporated.
Roll into 42 cake balls (about 1 heaping tablespoon per ball) and place on a baking sheet lined with parchment paper or a silicone baking mat, then transfer to the fridge or freezer to chill for 30 minutes.
In a microwave safe bowl, combine the white chocolate chips and vegetable oil. Microwave in 30 second intervals, stirring in between, until melted and smooth.
Working one by one, coat each cake ball in the melted chocolate. Using a fork, take each ball out of the bowl, shake off any excess chocolate, then return to the lined baking sheet and immediately sprinkle each one with the reserved cake crumbs.
Let the chocolate firm up before serving. To speed this up, place the truffles in the fridge for 30 minutes or in the freezer for 15.