Prepare your workspace by lining a baking sheet with parchment paper.
Melt the chocolate by combining semi-sweet chocolate chips and vegetable oil in a microwave-safe bowl. Microwave in 30-second intervals, stirring until smooth.
Dip each Oreo into the melted chocolate, ensuring it is fully coated, and let excess chocolate drip off.
Place the chocolate-covered Oreo onto the prepared baking sheet and repeat with the remaining cookies.
Decorate with sprinkles or drizzle with melted white chocolate if desired.
Allow the cookies to set at room temperature or refrigerate for 15-20 minutes until firm.
