Preheat your oven to 180°c (or 160°c for a fan-assisted oven or Gas Mark 4). Line a couple of sheets with some grease-proof paper. Set aside
In a large bowl, cream together the butter & sugar, until light and creamy.
Add the egg yolk, walnuts & vanilla, and mix until combined.
Gradually add the flour and cornflour to the mixture, a little at a time, mixing until it forms a soft dough.
Roll a small amount of dough into balls (between a teaspoon-tablespoon is ideal, depending on how big you want your biscuits to be) and place onto your pre-lined baking sheets with a bit of space between each ball. Flatten each ball a little with your fingers.
Bake in your preheated oven for 15 minutes, until golden and spread.
Leave on trays until cool enough to touch, before transferring to a wire rack to cool completely.
Notes
For full ingredient explanations, including substitutions, please see the Ingredients information above.
For hints and hacks for success, please see Granny's Top Tips above.
Once baked & cooled, Walnut Biscuits will be good for a few days, kept in an airtight container. As with most biscuits, they texture may change slightly over time.