Preheat the oven to 425°F (220°C). Grease a 9 x 13-inch baking pan and line it with parchment paper.
Whisk the eggs and sugar on high speed until thick, pale, and mousse-like, leaving a ribbon trail when lifted.
Sift together the flour and salt. Gently fold half into the egg mixture, then fold in the remaining flour until smooth.
Pour the batter into the prepared pan and spread evenly.
Bake for 9–10 minutes, until golden brown and springy to the touch.
Place a sheet of parchment paper on the counter and sprinkle with sugar.
Turn the hot sponge onto the sugared parchment and carefully remove the baking paper.
Score a shallow line about ¾ inch from one short end.
Roll the sponge up with the parchment paper inside and let cool completely on a wire rack.
Unroll the cooled sponge and trim the edges if desired.
Spread the jam or curd evenly, leaving a small border around the edges.
Spread the whipped cream over the filling.
Roll the cake back up without the parchment paper.
Place seam-side down, sprinkle with sugar, slice, and serve.