In a small bowl, whisk together the strawberry jam, water, and lemon juice until smooth.
In a medium mixing bowl, beat mascarpone cheese, heavy cream, sugar, vanilla extract, and lemon zest for about 2 minutes until thick, smooth, and fluffy.
Dip each ladyfinger briefly into the strawberry sauce, one at a time.
Arrange 12 dipped ladyfingers in a single layer inside an 8×8-inch baking dish.
Spread half of the mascarpone filling evenly over the cookies.
Add half of the sliced strawberries.
Repeat with another layer of dipped ladyfingers, remaining filling, and remaining strawberries.
Cover tightly with plastic wrap.
Refrigerate the No Bake Strawberry Tiramisu for at least 8 hours or overnight before serving for the best texture and flavor.