Preheat the oven to 225°F. Line a large baking sheet with parchment paper.
In a clean bowl, whisk the egg whites with the cream of tartar on medium speed until soft peaks form, 2–3 minutes. Increase to medium-high and gradually stream in 1 cup of the granulated sugar; continue whisking until very stiff, glossy peaks hold and the mixture feels mostly smooth when rubbed between fingers, 5–7 minutes total.
Spoon or pipe the meringue into 2–3 inch rounds on the prepared sheet. Bake until dry to the touch and they lift cleanly, 1 hour 30–40 minutes. Turn off the oven and let the meringues dry inside with the door cracked for 30–60 minutes, then cool completely.
While the meringues bake/cool, toss the strawberries with 2 tbsp of the remaining granulated sugar and the lemon juice. Let macerate until the berries release juices, 15–20 minutes, stirring once or twice.
In a chilled bowl, whisk the heavy cream, powdered sugar, and vanilla extract to soft peaks, 2–3 minutes. Keep cold.
Just before serving, reserve a few spoonfuls of the macerated strawberries and their juices for topping. Roughly crumble the cooled meringues into bite-size pieces.
Fold most of the crumbled meringue and most of the macerated strawberries with their juices into the whipped cream with a few broad strokes, leaving visible streaks—do not overmix.
Spoon into bowls or glasses, top with the reserved strawberries and juices, and serve immediately while the meringue is still crisp.