To make the crust: crush the graham crackers into fine crumbs. Stir in the sugar, salt, and melted butter and stir until the crumbs are evenly moistened and clump together when squeezed.
Preheat the oven to 350℉ and spray a 9" or 10" pie plate with cooking spray.
Pour the crumbs into the pie plate and press into a compact and even layer.
Bake for 10-12 minutes until light golden brown.
Make the strawberry topping: Heat 3.5 cups of the sliced strawberries with the lemon juice, and sugar, over medium high heat. Bring to a simmer and cook until the berries are tender (10 min).
Use a potato masher or a fork to mash the berries, with some large bits remaining.
Remove the berries from the heat and strain off 1/4 cup of liquid into a small bowl.
Add 2 tbsp cornstarch to the liquid and whisk til smooth.
Add the cornstarch mixture back to the strawberries in the pan and return to medium high heat. Cook until the mixture is simmering again and thickened, 1-2 minutes. The strawberry mixture should be bright red, thick, and jammy.
Remove the jam from the heat and let it cool completely. Once cooled, gently stir in the remaining sliced fresh strawberries. Transfer to a container and chill in the refrigerator.
Cream Cheese Filling: In the bowl of a stand mixer fitted with the whisk attachment, whip the heavy cream with 3 tablespoons of sugar on medium low speed until frothy. Turn up the speed to medium high speed and whip the cream to stiff peaks. Transfer the whipped cream to clean bowl. Do not wash out the mixing bowl.
Add the cream cheese to the mixing bowl with the remaining 1/3 cup of sugar, and beat on medium speed until smooth.
Scrape the bottom and sides of the bowl with a rubber spatula. Add the lemon zest, lemon juice, and vanilla extract and mix on medium speed until blended.
Next, stir two tablespoons of the whipped cream into the cream cheese mixture. Tip: No need to be careful about keeping the air in the cream at this step. The whipped cream here helps thin out the cream cheese, making it easier to fold in the rest of the whipped cream in the next step.
Gently fold in the rest whipped cream, being careful this time to keep as much air in the cream as possible. Fold until no more streaks of whipped cream is showing. Gently spoon the cream cheese filling into the cooled graham crust. Use a spoon to spread the filling to the sides in an even layer.
Chill the pie for 6 hours until set, overnight is best. Top with the chilled strawberry topping right before serving.