Take care of the jam. Put it in a dry and clean container and add soda. Stir and leave for 5 minutes. During this time, the components will react and the jam will rise.
In another bowl, beat the eggs. Add salt and beat quickly with a mixer for about 30 seconds. Gradually, in a thin stream, add sugar. Beat for another 3 minutes.
Add jam to the egg mixture. Then add vegetable oil and stir with a spoon until smooth.
Add the prepared flour and mix. If the dough seems too runny, add another 50-100 g of flour.
Start baking. Transfer the finished dough into the form. Put it in the oven and bake for 50 minutes. After that, take it out and wait until the sponge cake cools completely. Then take it out of the form.