1-Step 1: Prep the Pan Preheat oven to 350°F. Line a 9-inch square pan with foil, extending over edges. This lift-out trick simplifies cutting and cleanup.

2-Step 2: Mix and Bake the Bar Base In a medium bowl, stir or knead 1/2 cup chopped shelled pistachio nuts and 1/4 teaspoon green gel food color until well mixed. Press evenly into the pan bottom. Bake 15 to 20 minutes until golden brown. Cool completely, about 1 hour. This pistachio layer sets the Neapolitan ice cream bars base.

3-Step 3: Make the Filling Stir 1/4 cup white chocolate instant pudding mix with 1/4 cup melted butter until blended. Add 1/3 cup chopped maraschino cherries, 2 cups powdered sugar, and 1 tablespoon maraschino cherry juice. Adjust with more juice, 1 teaspoon at a time, for smooth creaminess. Spread over cooled base evenly. Pat cherries dry before chopping to avoid extra moisture.

4-Step 4: Prepare the Topping Place 1 cup semisweet chocolate chips and 1/4 cup butter in a microwavable bowl. Microwave on High 45 to 60 seconds, stirring every 15 seconds, until melted and smooth. Spread over filling right away.

5-Step 5: Chill and Cut Refrigerate 1 hour until set. Lift out with foil, peel away, cut into 4×4 pieces for 16 spumoni dessert squares. Store covered in fridge.

6-Step 6: Serving Tips Serve chilled. For parties, make ahead these make-ahead spumoni bars for parties hold up well. Pair with low-and-slow Texas brisket for a BBQ finish.

7-Step 7: Troubleshooting If filling is too thick, add juice slowly. Base not binding? Knead longer. Topping seized? Stir gently over low heat.

8-Step 8: Customize Swap green color for natural spinach powder if preferred. Add nuts to filling for crunch.