1. Weigh and measure all ingredients.
2. Preheat the oven to 180℃ fan/gas 6. Line the 20cm ( 8”) cake tin with parchment paper or grease well.
3. Shell and chop or blitz the pistachios.
4. Cream together the soft margarine, brown sugar & greek yogurt until light, pale & fluffy. This can take about 4 minutes.
5. Drizzle in the elderflower cordial and whisk until combined.
6. Crack in the eggs.
7. Sieve in the Odlums self-raising flour and baking powder.
8. Fold in the chopped pistachios.
9. Whisk until just combined. Using a spatula, pour the mixture into the lined tin.
10. Bake in the middle shelf of the oven for 35-40 minutes. I like to turn the oven down to 160℃ for the last 10 minutes. It will be a deep golden colour in top. Test with a cake skewer until it comes out clean. Allow the cake to cool in the tin for a few minutes, and pierce holes in the top with a straw or a skewer.
11. Drizzle on 50mls of the elderflower cordial. After another 10 minutes, remove the cake from the tin, and pop it on a stand. Slot a few pieces of parchment paper under the edges. This will catch any drips of icing. ( remove these before presenting)
12. While the cake bakes, make the icing. Whisk together the small cubes of soft real butter with the greek yoghurt. Sieve in the icing sugar and drizzle in the elderflower cordial. Go slowly until it forms a thick and spreadable icing. Drizzle the icing over the cooled cake.
13. Sprinkle with some chopped pistachio nuts & garnish with a little spring of elderflower on the side.

Notes: 

This cake is best served immediately on the day of baking. As the icing contains Greek yogurt the cake will need to be refrigerated if not eaten on the day.

Elderflower cordial can be replaced with the juice and zest of 1 lime or lemon in the cake and the 2 tsp juice in the icing.