Cut the butter into cubes and leave at room temperature to soften.
Preheat the oven to 170ºC.
Line the loaf tin with parchment paper.
Fit the Creaming beater to the machine.
Add the first two items of Ingredients 1 (butter, sugar) into the Mixer bowl.
Attach the Mixer bowl to the machine and fit the splash guard.
Mix on speed 1 for about 1 minute until combined.
Mix on speed 3 for about 5 minutes until light and fluffy.
While the machine is running, gradually add the next items of Ingredients 1 (eggs) into the Mixer bowl.
Add a spoonful of flour with each egg to stop the batter from curdling.
Mix on speed 3 for 2 minutes until fully combined.
Remove the Creaming beater, fit the K beater.
Sift in the next two items of Ingredients 1 (flour, baking powder) into the Mixer bowl.
Mix on speed Min for about 1 min until combined.
Add the seventh item of Ingredients 1 (ground almonds) into the Mixer bowl.
Mix on speed Min for about 30 seconds until combined.
Add the remaining Ingredients 1 (orange flower water) into the Mixer bowl.
Mix on low speed for about 20 seconds until combined.
Spoon the batter into the prepared loaf tin and smooth the top.
Bake at 170ºC for about 45-60 minutes until a skewer inserted tests clean.
Remove from the oven and let to cool in the tin for 10 minutes.
Turn onto a cooling rack to cool completely.
Remove the K beater, fit the Creaming beater.
Add Ingredients 2 (mascarpone, caster sugar, orange flower water, vanilla extract) into the Mixer bowl.
Mix on speed 1 for about 5 minutes until fluffy and smooth.
Once the cake is completely cool, top with frosting.
Decorate with slivered pistachios and candied orange slices.