Preheat oven to 177°C (gas mark 4.5). Prepare a baking tray lined with baking paper.
In a large mixing bowl, cream together the vegan margarine, sugar and vanilla extract with a folk or a whisk until fluffy.
Add in the flour and salt and combine well until it forms a dough. if necessary, use your hand to form the dough.
Pick up an amount of a meatball (about 20-23 grams) and roll it in your hands. Place in the prepared baking tray. The dough should be very soft and quite sticky but you will manage this! Repeat the step to make the rest of the cookies. Please make sure you leave enough space between the cookies as they go bigger when baked.
With your finger, gently press the centre of each ball to make a hollow. Placing a bit of clingfilm over the balls when pressing prevent your finger sticking the dough.
Give your jam a good stir so that there are no lumpy bits in it. Gently put small amount of the jam (about 1/2 tea spoon) in each hollow of the cookies. Careful not to put too much, it might drip down to the bottom of the cookies while baking otherwise!
Put the baking tray with the cookies in the fridge for 30 minutes. The cookies will firm up a bit that will keep the cookie shape nicely.
Bake for 10-12 minutes and let them cool down completely before serving.