Preheat oven to 200°C (390°F) or 180°C (360°F) for fan-forced ovens. Line and grease the base and sides of 2 x 15cm (6in) or a 23cm (9in) round cake tin with nonstick baking paper.
Using a stand or hand mixer beat the butter, sugar and zest first on low speed to avoid splatter then increase then speed to high and beat for 3 minutes. Add in the eggs one at a time whilst continuing to beat in between, pour in the orange juice and yoghurt and beat for a further minute.
Divide the batter evenly into the prepared tins, using a flat spatula or a butter knife smooth the surface then tap the pans against the table a few times. Place the tins into the oven on top of the middle rack. Bake for 38 to 40 minutes or until the top of the cake is golden and a skewer comes out clean when inserted in the middle.
Prepare the syrup when the cake has 10 minutes left to bake. In a small saucepan combine the honey, rosewater, lemon juice, water and salt, cook on medium heat as soon as it starts to bubble decrease and let it simmer softly for 5 minutes.
As soon as the cakes come out of the oven use a skewer to poke several holes in the cakes, making sure the skewer reaches the base of the cakes. Whilst the cake and syrup is hot, use a spoon to coat each cake in syrup. Avoid putting too much syrup in the centre of the cakes as the middle may get soggy. Leave the cakes to cool in the tin at room temperature (1 to 2 hours)
In a small bowl add in the icing sugar and 3 tablespoons of lemon juice, mix until combined. Check it for preferred consistency, for a runny icing, slowly add more juice and continue to mix until the icing runs off the spoon but it should still be thick. Use a spatula to spread the icing over the cakes, decorate it with rose buds and sliced pistachios.