Melt the 8 tablespoons of unsalted butter in a large saucepan over medium heat, stirring occasionally.
Add 2 bags of miniature marshmallows to the saucepan and stir continuously until fully melted and smooth, about 5 minutes.
Sprinkle in the 1/2 teaspoon of kosher salt and stir well to combine.
Remove from heat and gently fold in 9 cups of Rice Krispies cereal until well-coated.
Lightly grease a 9x13-inch baking dish or line with parchment paper.
Pour the mixture into the prepared baking dish and press it down firmly and evenly.
Melt the 3 bars of Ghirardelli white chocolate in a microwave-safe bowl in 30-second intervals, stirring until smooth. Add pink candy coloring to achieve desired shade.
Drizzle the melted pink chocolate over the Rice Krispies mixture and sprinkle with colorful sprinkles before the chocolate sets.
Allow the bars to cool at room temperature for about an hour or refrigerate for quicker cooling.
Once set, lift the bars out using parchment paper edges, slice, and serve.
