Preheat the oven to 180 C / Gas 4. Grease two 20cm cake tins and line with baking parchment.
In a bowl, beat together the butter and sugar until light and fluffy. Add in the eggs, one at a time, beating well after each addition. Fold in the flour and add the salt and vanilla.
Divide the mixture evenly between the two prepared cake tins and smooth the top.
Bake in the preheated oven, on the same shelf, for 20 to 25 minutes until a skewer inserted into the centre comes out clean. Remove from the oven and cool on a rack for 90 minutes.
When completely cool, remove the baking parchment and sandwich the two cake layers together with the jam and cream, shaving a little off the top of the bottom layer if necessary to provide an even surface. Dust with icing sugar and serve.