Walnut Slice with Egg Yolk Glaze

Preheat the oven to 160 °C. Line a baking tray with baking paper.

Cream the butter with the sugar until fluffy. Add the plain flour and finely ground walnuts. Beat the egg whites until stiff peaks form, then gently fold them into the batter in several additions.

Spread the batter evenly in the baking paper-lined tray, making sure it reaches the edges. Place the tray in the preheated oven and bake for 30–35 minutes.