Preheat oven to 190 degrees C. Grease baking trays.
Cream the butter and sugar until light and fluffy. Beat in the egg yolk and vanilla essence. Sift together the flour, cornflour and salt; stir into the butter mixture. Shape dough into 20 to 24 small balls, about 2cm in diameter. Roll each ball in the oats and place about 5cm apart on baking trays.
Bake 15 to 20 minutes until golden brown. Let cool on wire rack. Store in an airtight tin.
I made these bigger than stated in the recipe and got 11 biscuits. Next time I make them I will double if not triple the ingredient amounts because they are such beautiful tasting, and textured biscuits. Slightly crunchy on the outside and so fluffy on the inside. And the oats give them that extra something. The whole family loved these. Absolutely delicious and simple to make. - 03 Aug 2013