Preheat oven to 250°F.
Make 6 heart stencils on parchment paper using a cookie cutter and a pencil.
Transfer the parchment to a large rimmed baking sheet with the pencil side facing down.
Using a hand mixer or stand mixer with whisk attachment, beat egg whites until frothy.
Add salt and cream of tartar and continue beating while adding the sugar in tablespoon increments until meringue is glossy with stiff peaks.
Sprinkle lemon juice and crushed conversation heart candies, and gently fold to combine.
Place meringue in a pastry bag or plastic bag with tip cut off and form into hearts.
Bake for 1 hour, turn the oven off and let it cool completely in the oven, about 1 hour.
Once completely cool, add whipped cream, diced fruit and lightly dust with powdered sugar and more conversation hearts.
For the strawberry whipped cream:
Using a stand or hand mixer set to medium-high speed, whip the heavy cream until soft peaks form, about 2 minutes.
Reduce speed to low and slowly mix in the jam until well combined.
Fold in diced strawberries and serve immediately.