**Prepare the pan**
Line a 9x13-inch baking dish or sheet pan with parchment paper, leaving some overhang for easy removal.
**Melt the white chocolate**
In a microwave-safe bowl, melt the white chocolate in 30-second intervals, stirring after each interval, until smooth and fully melted.
**Add the peanut butter**
Stir the peanut butter into the melted white chocolate until completely combined and smooth.
**Spread the base layer**
Pour the white chocolate and peanut butter mixture into the prepared pan, spreading it evenly with a spatula.
**Melt the milk or dark chocolate**
In another microwave-safe bowl, melt the milk or dark chocolate in 30-second intervals, stirring after each interval, until smooth.
**Add the swirls**
Drizzle the melted milk or dark chocolate over the white chocolate and peanut butter layer. Use a toothpick or skewer to create swirls by dragging it through the chocolate in a zigzag or circular pattern.
**Chill**
Refrigerate the tiger butter for about 1 hour, or until completely set.
**Cut and serve**
Once set, lift the tiger butter out of the pan using the parchment paper. Cut into squares or break into pieces and serve.
