Preheat the oven to 180 C / Gas 4. Line a baking tray with baking parchment.
In a mixing bowl, cream together the softened butter with cream cheese and soured cream. Add flour, a pinch of salt, and form into a dough. Shape into a ball then wrap in cling film and place in the fridge to chill for 1 hour.
Turn out onto a floured work surface, or place on a sheet of cling film. Roll out flat, 3mm thick. You can divide into 3 to 4 parts and work it one part at a time if preferred. Cut out circles using a biscuit cutter, place some jam in the centre and pinch the edges together, shaping into an envelope. Use leftover dough to make more circles and fill until the ingredients are used up. Transfer to the prepared baking tray.
Bake in the preheated oven for 20 minutes until golden brown. Remove from the oven and allow to cool on a cooling rack before serving.
When rolling, it helps to cover the surface and dough with cling film, to prevent the dough from sticking and to avoid using too much flour.