Step 2: Bake
Pour the batter into the prepared pan and bake for 30–35 minutes, or until a toothpick inserted in the center comes out clean. Allow the cake to cool completely before frosting.
Step 3: Make the Frosting
In a bowl, whisk together the second box of pistachio pudding mix and the milk until thickened.
Gently fold in the Cool Whip until smooth and fluffy.
Step 4: Frost and Chill
Spread the frosting evenly over the cooled cake. Refrigerate for at least 2 hours before serving.
Garnish with chopped pistachios if desired.
