Preheat oven to 180C or 160C fan. Lightly grease 2 x 20cm (base measurement) round cake tins and line the bases with non-stick baking paper. Using electric beaters, beat eggs in a large bowl for 5 mins, until thick, pale and increased in volume. Add sugar, 2 tbsp at a time, beating well after each addition. Beat in vanilla.
Sift flour over egg mixture. Using a large metal spoon or rubber spatula, fold in until combined, taking care not to lose volume. Divide evenly between prepared tins.
Bake for 18-20 mins, until the cakes spring back to a light touch in the centre. Cool in tin for 5 mins, then turn out onto a wire rack and peel away the paper. Leave to cool
Place 1 cake onto a serving plate and pipe or dollop with the whipped cream. Spread the other sponge with jam and invert onto the bottom cake. Put icing sugar into a small sieve and dust top of cake. Top with strawberries.