Macerate the strawberries Place the sliced strawberries in a medium bowl. Sprinkle with the 3 tablespoons sugar and lemon juice. Gently toss and let sit for 10–15 minutes. The berries will release glossy red juices that form a light syrup.
Whip the cream Pour the cold heavy cream into a large chilled bowl. Add powdered sugar, vanilla, and the pinch of salt. Whip with a hand mixer or stand mixer on medium-high speed until soft-to-medium peaks form, about 2–3 minutes. Stop when the cream holds its shape but still looks smooth and billowy. Do not overwhip.
Prep the cake Cut the cake into roughly 1-inch cubes. If the cake feels very dry, you can lightly brush a few cubes with a spoonful of the strawberry juices later.
Layer the dessert Choose individual glasses, jars, or a trifle dish. Place a layer of cake cubes in the bottom. Spoon over some of the macerated strawberries and their juices so the cake begins to soften. Add a generous layer of whipped cream. Repeat the layers once or twice, ending with cream and a few pretty strawberry slices on top.
Chill briefly (optional but recommended) Refrigerate for 10–15 minutes so the flavors settle and the cream firms slightly. Serve cold.
