Lockdown Almond & Orange Slice

Introduction
Here's an easy slice similar to a shortbread, with a hint of cinnamon and orange and a nutty top. It'll keep for several days, though you'll probably eat it before then!
Serves: Makes 18 slices
Ingredients
150g (5 oz) unsalted butter, softened
¼ cup caster (superfine granulated) sugar
1 cup standard flour, plus extra for pressing out
½ tsp ground cinnamon
Finely grated zest ½ an orange
A little beaten egg white, for glazing
¼ cup slivered almonds
½-1 Tbsp caster (superfine granulated) sugar
Method
1 Preheat oven to 180°C (350°F). Line a Swiss roll tin (jellyroll pan, 22cm x 20cm / 8½” x 8” or similar) with baking (parchment) paper (or make a paper case to sit inside a shallow tin, securing the edges with paper clips).
2 The butter should be very soft, but not oily. Put butter in a bowl and beat with a hand-held electric beater until smooth (or whiz in a food processor then transfer to a bowl). Slowly beat in sugar and continue beating until lighter in colour (creamed). Sift flour and cinnamon over the top and add orange zest. Work together with a rubber spatula until mixture is smooth.
3 Press into prepared tin with floured fingers, making it smooth. Brush with beaten egg white and prick with a fork. Sprinkle over almonds and a little sugar.
4 Bake for 15-20 minutes until lightly golden. Cool in the tin or paper case for 10 or so minutes and mark into squares while still warm. When cool, transfer to an airtight container.
