Step 1: Prepare the Crust

1. Preheat oven to 350°F (175°C).

2. Place a glass or metal mixing bowl in the refrigerator to chill for the whipped cream.

3. In a medium bowl, combine 2 cups graham cracker crumbs, 7 tablespoons melted unsalted butter, and ¼ cup white sugar until well-mixed and crumbly.

4. Press the mixture firmly into the bottom and up the sides of a 9-inch pie plate, using a spoon or flat-bottomed glass to compact it.

5. Bake in the preheated oven for 7 minutes until firm. Let cool completely, about 20 minutes.

6. Tip: Press the crust evenly to avoid crumbling, and cool fully to ensure the filling sets properly.

Step 2: Make the Filling

1. In the chilled bowl, beat 2 cups heavy whipping cream with a hand mixer on medium-high speed until stiff peaks form, about 2–3 minutes.

2. In a separate large bowl, stir together 1 (14-ounce) can sweetened condensed milk and 1 (6-ounce) can frozen lemonade concentrate (not thawed) until fully combined.

3. Gently fold the whipped cream into the lemonade mixture with a spatula until smooth and uniform.

4. Tip: Chill the bowl and beaters for faster whipping, and fold gently to maintain the filling’s airy texture. Ensure the lemonade concentrate is mixed thoroughly to avoid icy patches.

Step 3: Assemble

1. Pour the lemonade filling into the cooled graham cracker crust, smoothing the top with a spatula for an even surface.

2. Tip: Tap the pie plate gently on the counter to remove air bubbles and ensure a level filling.

Step 4: Freeze

1. Cover the pie with plastic wrap or foil.

2. Freeze for 8 hours or overnight until fully set and firm.

3. Tip: Ensure the freezer is at 0°F (-18°C) or colder to achieve a solid, sliceable texture.

Step 5: Prepare the Berry Topping

1. In a medium bowl, toss 1 cup sliced strawberries, ½ cup blackberries, and ½ cup raspberries with 2 tablespoons lemon juice and 2 tablespoons white sugar until well-coated.

2. Let the berries sit for 5–10 minutes to release juices, stirring occasionally.

3. Tip: Use fresh, ripe berries for the best flavor, and prepare the topping just before serving to keep it vibrant.

Step 6: Serve

1. Remove the pie from the freezer and let sit at room temperature for 10 minutes to soften slightly for easier slicing.

2. Slice into 8 equal portions using a sharp knife dipped in hot water and wiped dry.

3. Top each slice with a spoonful of the mixed berry topping and serve immediately.

4. Tip: Serve frozen for a refreshing texture, and add the berry topping just before serving to prevent it from soaking into the pie.