Preparation

• Begin by thawing the whipped topping if necessary. Let the cream cheese sit at room temperature to soften for about 45 minutes. Prepare an 8x8-inch baking pan by lining it with two sheets of parchment paper, overlapping them for easy lifting.
• Melt the butter in a large microwave-safe bowl for 40 to 60 seconds, or on the stove if preferred.
• Break the shortbread cookies into pieces and blend them in a food processor until you achieve fine crumbs, approximately 15 to 20 short pulses. If you don't have a processor, you can place the cookies in a bag and crush them with a rolling pin.
• Pour the melted butter over the cookie crumbs and sprinkle in 1/4 teaspoon of salt. Blend until the mixture resembles wet sand and sticks together when squeezed. If mixing by hand, combine the crumbs in a bowl with the butter and salt until the desired texture is achieved.
• Press the crumb mixture into the prepared pan evenly using a measuring cup or your fingers to reach all sides. Clean the food processor bowl and blade.
• Zest the lemon using a grater and extract the juice, yielding about 2 tablespoons. Place both the zest and juice in the cleaned food processor along with the cream cheese, powdered sugar, and the remaining 1/4 teaspoon of salt. Blend until smooth and airy, roughly 1 minute.
• Take half of this cream cheese mixture and place it in the reserved butter bowl. Mix in 1 cup of whipped topping with a spatula until fully blended and smooth. Spread this layer evenly over the crust.
• Crush the freeze-dried strawberries in a sealed bag using a rolling pin until they become a fine powder. Set aside 2 tablespoons of this powder in an airtight container for later use.
• In the food processor, add the remaining strawberry powder and the strawberry preserves to the leftover cream cheese mixture. Blend until perfectly smooth, about 30 seconds to 1 minute. Transfer this mixture to the butter bowl and incorporate 1/2 cup of whipped topping thoroughly. Spoon this strawberry layer over the lemon layer and smooth it out.
• Dollop the remaining whipped topping over the strawberry layer and spread it into an even layer. Cover the pan with plastic wrap and chill in the refrigerator until set, at least 4 hours or overnight.
• Using the parchment paper, lift the dessert out of the pan onto a cutting board. Dust the top with the reserved strawberry powder using a fine-mesh strainer. Cut into 9 bars, cleaning the knife after each slice for neat edges.