Preheat the oven to 190°C and line a 23x33cm Swiss roll tin with baking parchment.
Whisk eggs, sugar, and vanilla seeds in a bowl until light, fluffy, and thickened.
Sift flour over the egg mixture and fold it in carefully.
Pour mixture into the tin and smooth evenly with a spatula.
Bake the sponge for 10 to 12 minutes until just firm.
Dust a large sheet of parchment paper with caster sugar.
Turn the sponge onto the sugared paper and peel off the original parchment.
Whip double cream and vanilla extract to soft peaks.
Heat a frying pan and cook jam sugar with lemon juice and zest for 4 minutes.
Add berries to the pan and cook for 5 minutes until thick, then cool.
Spread cooled jam over the sponge leaving a 2cm border.
Layer whipped cream over the jam and sprinkle with whole raspberries.
Roll the sponge tightly from the long edge using the parchment paper to assist.
Remove parchment, dust with sugar, and slice to serve.