2) In the bowl of an electric mixer fitted with the paddle attachment mix together the butter and sugar until they are just combined. Add the vanilla.
3) In a medium bowl sift together the plain flour and salt then add them to the butter and sugar mixture. Mix on low speed until the dough starts to come together.
4) Dump onto a surface dusted with plain flour and shape into a flat disk. Wrap in cling film and chill for 30 minutes.
5) Roll the dough 1/2cm thick and cut 7cm rounds with a plain or fluted cutter. With half of the rounds cut a hole from the middle of each round with a heart or spade shaped cutter. Place all the cookies on an ungreased baking sheet and chill for 15 minutes.
6) Bake the cookies for 20 to 25 minutes until the edges begin to brown.
7) Remove from oven and allow to cool to room temperature. Spread raspberry preserve on the flat side of each solid cookie. Dust the top of the cut-out cookies with icing sugar and press the flat sides together with the raspberry preserve in the middle and the icing sugar on the top.