In a mixing bowl, beat egg whites and cream of tartar on medium speed until soft peaks form. Gradually beat in sugar 1 tablespoons at a time, on high until stiff glossy peaks form and sugar is dissolved. Fold in the crackers, pecans and vanilla.
Spread onto the bottom and up the sides of a greased 10-inch deep pie pan. Bake at 350F for 25-30 minutes or until meringue is lightly browned. Cool on a wire rack. Set aside 1 strawberry for garnish.
Slice half the strawberries and set aside. In a bowl, mash the remaining strawberries; drain juice, reserving 1/2 cup. In a saucepan, combine marshmallows and reserved juice. Cook and stir over low heat until marshmallows are melted. Refrigerate until partially set.
Fold the sliced and mashed strawberries and whipped topping into marshmallow mixture. Spoon into meringue shell. Garnish with reserved strawberry.