Spray a 9×13” pan with cooking spray and set aside.
In a large microwave-safe bowl, melt the butter in 15-second increments.
Add 3/4 of the marshmallows to the melted butter and continue melting in 30-second increments, stirring between each round, until fully melted and combined.
Fold the Rice Krispies cereal into the melted butter and marshmallows mixture and mix well. Stir in the remaining mini marshmallows (they won’t fully melt, leaving a chewy texture).
Press the Rice Krispie mixture into the prepared pan and let it cool.
In a separate bowl, beat the softened cream cheese, sweetened condensed milk, lemon juice, and vanilla extract together until smooth and creamy.
Add 1 drop of yellow food dye to the cheesecake mixture and stir until evenly colored.
Pour the cheesecake mixture over the cooled Rice Krispie layer and use a spatula to smooth the top.
Refrigerate the treats for 3-4 hours or until the cheesecake layer is set.
Once set, remove from the refrigerator and cut into squares.
Melt the white chocolate in 30-second increments, stirring until smooth, then drizzle over the bars.
Garnish with lemon zest for a fresh touch (optional). Enjoy!