Heat the oven to 160C fan/gas mark 4.
Cut
the butter roughly into pieces and cream in a food mixer until pale.
Add the sugar and vanilla seeds and continue to mix until pale again.
Mix in the egg yolk and the maple syrup.
Roast the walnuts for 5-10
minutes in the hot oven, leave to cool and coarsely chop. Turn off the
oven.
Add the flour and chopped walnuts to the
butter mix and combine until a dough forms. Knead this deftly and
swiftly on a lightly floured surface.
Once the
dough is formed, shape into a cylinder roughly 30cm in length and 5-6cm
in width. Cut in half and roll each half in a sheet of greaseproof
paper, twisting the ends as if for a large bonbon.
Refrigerate for at least 30 minutes (if desired, one of the halves can be frozen for another time).
Heat
the oven again to 160C fan/gas mark 4. Line a baking sheet with baking
parchment. As these are best eaten fresh, slice and bake only what is
needed, then rewrap, store and return to the fridge. Cut 3mm-thick
slices and lay in serried ranks on the lined baking sheet.
Place in the oven and bake for 12-15 minutes. Cool on a rack.
From Cooking: Simply and Well, for One or Many by Jeremy Lee (HarperCollins, £30)