Place 1/2 cup cold water in a small bowl; sprinkle the gelatin on top and let stand for 5 minutes to soften. Transfer to the microwave and cook at medium power until melted and smooth, 30 seconds.
Set aside 8 perfect strawberries and 8 crackers for a garnish. Hull and slice the remaining strawberries. Transfer 1 1/2 cups of the berries to a food processor; add the sugar and process until pureed. Add the gelatin and process briefly to bend. Strain the berry puree through a fine-mesh sieve, pressing and stirring with a spatula as needed, to remove any seeds.
Using an electric mixer, whip the heavy cream until stiff. Whisk in the strawberry puree. Add the marshmallow cream, mixing at low speed, then increasing to medium, until nearly smooth. (The mixture will seem thin, but it will set in the refrigerator.)
Lightly grease an 8-inch springform pan. Place a layer of crackers on the bottom of the pan to cover, breaking a few of them in half as needed to fit into an even layer. Spoon one-third of the marshmallow mixture on top; top with another layer of crackers, then spoon half of the sliced berries on top. Add another third of the marshmallow mixture, another layer of crackers and the remaining sliced berries. Top with the remaining marshmallow mixture. Arrange the reserved 8 crackers to form a ring along the outside edge. Refrigerate the cake overnight.
Halve the 8 reserved strawberries and place on top of the crackers. Cut the cake with a warmed thin, sharp knife.