2) Using an electric mixer, beat the butter, sugar, vanilla, fennel seed and salt in a large bowl until light and fluffy. Beat in the egg. Add the flour and mix just until blended.
3) Transfer the dough to a sheet of cling film. Shape the dough into a 20cm-long log, wrap in cling film and refrigerate for 2 hours.
4) Remove the cling film and cut the dough log crosswise into 1/4 to 1/2cm thick slices. Transfer the biscuits to the prepared baking sheets, spacing them evenly apart. Press the pine nuts decoratively into the top of the biscuits.
5) Bake until the biscuits are golden around the edges, about 15 mins. Allow to cool and store in an airtight container.