Prepare the berries. Wash strawberries, dry them thoroughly, remove the stems, and cut into thin even slices. Reserve a few for the top.
Chill a mixing bowl and beaters briefly. Add cold heavy cream, powdered sugar, and vanilla, then beat until medium-stiff peaks hold.
Spread a thin layer of whipped cream across the base of the dish. This helps the first crackers stay in place during assembly.
Arrange one layer of graham crackers over the cream, breaking pieces to fit. Spread with one-third of the remaining cream and a layer of strawberries.
Repeat the crackers, cream, and strawberries twice more. Use roughly equal portions so every slice contains a balanced set of layers.
Cover without pressing the wrapping into the topping. Refrigerate for at least 6 hours, preferably overnight, until the crackers soften completely.
Check a corner with a thin knife; it should pass through the cracker layers with little resistance. Keep the cake chilled until serving.
Add reserved berries shortly before serving. Cut into squares with a sharp knife and lift portions with a broad spatula.
