Preheat the oven to 350 degrees F (175 degrees C).
Beat flour, butter, powdered sugar, and egg yolks together in a large bowl. Press into the bottom of a 9x13-inch baking pan.
Bake in the preheated oven until lightly golden, about 12 minutes.
Meanwhile, beat egg whites with an electric mixer until foamy. Gradually add white sugar, continuing to beat until stiff, shiny peaks form. Fold in rice vinegar and cornstarch with a spatula.
Remove crust from the oven; cover with jam. Spoon meringue over the top. Continue baking until meringue is golden brown, about 25 minutes. Let cool completely before cutting into bars.
