Using a food processor, break up the crackers, and pulse until you have crumbs. Alternatively, place the crackers in a Ziplock bag, release as much air as possible, and use a rollign pin to gently pound and roll into crumbs.
In a medium bowl, combine graham cracker crumbs, sugar, and butter, and mix well.
Press into pie plate.
Bake at 350 for 7 minutes.
To make the filling
Mix cornstarch with a couple of tablespoons (or more) of water and mix well. It should be a white liquid with no lumps. Set aside.
Place 1 cup of water, 1 cup of sugar, 1 teaspoon salt and 1 cup of blueberries in a medium saucepan.
Bring to a boil and boil for 1 minute.
Remove from heat and add cornstarch slurry.
Return to heat, bring a boil until mixture is thick and shiny.
Remove from heat and add 1 Tbs butter.
When the mixture is cooled, gently fold in 3 cups of fresh berries.
Pour the blueberry mixture into the pie crust.
Top with remaining 1 1 /2 cups fresh blueberries.
Chill until set (about 3 hours)
To make the topping
Combine heavy cream, sugar, lemon zest and lemon juice in a stand mixer.
Beat until soft peaks form.
Serve pie chilled topped with lemon whipped cream.
Cool means really cool! Make sure there is not a bit of warmth left in your filling, this helps it set up best.
You can use a hand mixer to beat your whipped cream if you don't have a stand mixer.
Chilling your bowl and beaters/wire whisk helps make whipped cream faster and keeps it from warming up.
A store-bought graham cracker crust will work if you don't want to make your own, but I still prefer the homemade version.