Preparation:

1. Prepare the dough:
1. Preheat the oven to 180°C (350°F).
2. In a large bowl, beat butter and sugar until smooth and creamy.
3. Add the eggs one at a time, beating well after each addition.
4. Add orange zest and vanilla essence (if using).
5.Sift flour and baking powder into the resulting mixture and mix carefully.
6. Add the orange juice and stir until a homogeneous mass is formed.
7. Pour the mixture into a buttered and floured mold.
8. Bake for 30 to 35 minutes or until a toothpick inserted into the center comes out clean.
9. Allow to cool in the tin for a few minutes and then leave to cool completely on a wire rack.
2.Glaze (if you want):
1. Mix the powdered sugar with the orange juice until a smooth, free-flowing mixture is formed.
2. Pour the icing over the cooled cake.