In a large bowl, beat the cold heavy cream, powdered sugar, and vanilla extract until stiff peaks form.
Spread a thin layer of whipped cream on the bottom of a 9x13-inch dish to lightly coat the base.
Arrange a single layer of graham crackers over the whipped cream, breaking them as needed to fit.
Spread about 1/3 of the whipped cream evenly over the graham crackers.
Layer 1/3 of the sliced strawberries over the whipped cream.
Repeat the layers two more times: graham crackers, whipped cream, strawberries.
Finish with a final layer of whipped cream and garnish with any remaining strawberries.
Cover and refrigerate for at least 4–6 hours (overnight is best) to allow the graham crackers to soften into a cake-like texture.
Slice and serve chilled!