Pre-heat your oven to 180°c (160°c for fan assisted oven, Gas Mark 4 or 350°F) and line 2-3 baking sheets with some greaseproof paper. Set aside.
In a large bowl, whisk you eggs for 2 minutes until they are foamy. You can do this by hand but it will be much quicker & easier using a handheld whisk or a stand mixer.
Add the sugar to the eggs and continue to whisk for a further 8 minutes, until the mixture is pale, fluffy and thick.
Add the vanilla to the mixture, before sifting in the flour and baking powder. Gently fold the flour through, being cautious to not mix too vigorously - you want to keep as much air in the batter as possible.
Spoon a tablespoon of the batter onto your pre-lined baking sheet. Repeat with the rest of the batter, leaving plenty space between each spoonful - they will spread as they bake. You should get around 16-18 spoonfuls.
Bake in your pre-heated oven for 8-10 minutes, until they are a pale golden colour. Remove from the oven and allow to cool on the baking sheets.
Once completely cool, whip the double cream in a bowl until it has medium-stiff peaks. Add a spoonful of jam to half of the sponge drops, and a spoonful of cream to the other halves. Sandwich the jam and cream halves together and dust the tops with a little icing sugar, if desired. Serve immediately.