Orange Cake 

500g butter

500g castor sugar

3 tbsp grated orange zest

500g self-raising flour

200ml freshly squeezed orange juice

8 eggs

1/2 teaspoon vanilla essence

few drops lemon juice

1. Heat the oven to 170C/Gas 3. You will need a 30 cm cake tin with removable sides,  well-greased with butter.
   
2. Cream butter and sugar well, until it is very pale and thick - this will take quite a while.
   
3. Add the eggs one by one, beating well after each addition, and the zest, if using. Add the flour all at once, and beat well, then slowly add the orange juice, until it is incorporated.
   
4. Pour the batter into the prepared cake tin, and bake for 1 hour and 10 minutes - or until an inserted skewer comes out clean.