Tiger Butter Fudge

Line a 9-by 9-inch pan with foil, leaving a 2-inch overhang on two sides. Coat the foil with cooking spray. Place 2 cups milk chocolate chips and 1 can condensed milk in a large microwave-safe bowl and heat, stirring every 30 seconds, until melted and smooth, about 2 minutes. Transfer the mixture to the prepared pan. Place the white chocolate chips, peanut butter chips and remaining can condensed milk in a clean large microwave-safe bowl and heat, stirring every 30 seconds, until melted and smooth. Spread the white chocolate mixture evenly over the chocolate mixture. Place the remaining 1/2 cup milk chocolate chips and the vegetable oil in a small microwave-safe bowl and heat, stirring every 20 seconds, until melted and smooth. Drizzle over the fudge, then refrigerate until firm, about 1 hour. Using the foil overhangs, lift the fudge from the pan and transfer to a cutting board. Cut into 25 squares. Store in an airtight container up to 1 week.