Line a 9x13-inch baking dish with parchment paper or spray it with nonstick cooking spray.

In a large pot, melt the butter over medium-low heat.

Once melted, add the mini marshmallows and stir until smooth.

Remove from heat, stir in vanilla extract and green gel food coloring.

Fold in the Rice Krispies until well-coated.

Press the mixture into the prepared baking dish.

Let the mixture cool at room temperature for about 20 minutes.

Once set, cut into long rectangles and then diagonally for tree shapes.

Melt white chocolate chips in the microwave until smooth.

Pipe the melted chocolate across the tops of each tree-shaped treat.

Decorate with star-shaped sprinkles and mini M&Ms.

Allow the chocolate to harden completely at room temperature.