Crush the vanilla cookies or graham crackers (run through a food processor or put them in a gallon zip-top bag and roll over them with a rolling pin). Mix crumbs with melted butter, then press tightly into a pie pan.
Bake for 8 minutes, then cool on a wire rack.
Filling
Combine 2 cups of berries with 1/2 cup sugar and 2 Tablespoons of water in a sauce pan on the stove. Bring to a full boil.
Dissolve cornstarch in 1/4 cup water and add to the sauce pan. Mixing constantly, return mixture to a full boil, then reduce heat to low and cook for 2 minutes.
Remove from heat, add butter, lemon juice, and remaining berries. Mix until well combined, then spoon into crust.
Let stand or chill for 3 hours, until set.
Notes
Make this gluten free by using a gluten free crust. You may be able to substitute gluten free cookies to make the crust, but I haven't tried that to verify it will work.Make this dairy-free/vegan by substituting margarine or a vegan butter.