Preheat oven to 350°F (180°C). Grease a 9×13-inch baking dish.
In a large bowl, combine cake mix, strawberry gelatin, eggs, melted butter, and milk. Mix until smooth.
1 white cake mix, 3 ounces strawberry gelatin, 4 eggs, ½ cup unsalted butter, 1 cup milk
Pour the batter into the prepared pan and bake for 28–30 minutes, or until a toothpick comes out clean. Let the cake cool completely.
In a food processor, pulse the cookies into coarse crumbs and the freeze-dried strawberries into powder. Mix them together in a bowl, then stir in the melted butter until combined. Set aside.
1 ounce freeze-dried strawberries, ¾ cup unsalted butter, 2 cups vanilla sandwich cookies
In a large bowl, beat cream cheese, butter, and salt until smooth. Add vanilla. Gradually mix in powdered sugar, then add milk one tablespoon at a time to reach desired consistency.
¼ cup unsalted butter, 8 ounces cream cheese, ½ teaspoon vanilla extract, 3 cups powdered sugar, 2 tablespoons milk, ¼ teaspoon salt