Heat your oven to 180°C/160°C fan/Gas mark 4
Grease your cake tin and line the base with greaseproof paper.
Cream together your butter and sugar, until light and fluffy and pale in colour.
Sift together your flour and baking powder and set aside.
Add your beaten egg and two tablespoons of the sifted flour and baking powder to the butter and sugar mix and beat together on a medium setting until combined.
Add in all of the rest of your ingredients and beat on medium setting until just combined, The mixture will be quite stiff.
Add the mixture to your tin and smooth out, with the back of a spoon.
Place a piece of clingfilm on top and smooth the batter out underneath, this gives an even finish.
Brush over your egg wash, you may not need all of it.
Sprinkle over your flaked almonds.
Bake in the centre of your oven for 25-30 minutes or until a skewer inserted in the centre comes out clean.
Leave to cool in the tin, the butter cake is quite thin and will break if you take if out before it has set.