Preheat the oven to 190°C/170°C fan and lightly grease a baking sheet.
Sift the flour into a baking sheet, add the salt and the lard and rub together until they resemble breadcrumbs. Then add the ice-cold water, a little at a time, and combine until the pastry forms a ball. With floured hands, roll the dough into a sausage. Wrap in clingfilm and chill for 30 minutes.
To make the filling, mix the peanut butter with the sugar and mixed essence. Remove the pastry from the fridge and cut into 12 equal parts and roll into balls. Flatten the balls into discs in the palm of your hands and fill each one with one teaspoon of the filling. Seal up the edges and pat flat, to about 1.5cm thick.
Brush each biscuit with the egg wash and place on the prepared baking sheet. Bake for 15 – 20 minutes until golden brown. Remove from the oven and let the biscuits cool.
To make the glace icing, sift the icing sugar in a bowl and gradually add water until the icing is smooth and can coat the back of a spoon. Once made spoon over the cookies and top with a seasonal sugar cake decorations.