Preheat oven to 180 degrees C. Grease and flour two 20cm round cake tins. Sift flour, salt and baking powder together and set aside.
In a large bowl, cream butter, margarine and sugar until light and fluffy. Add eggs one at a time and beat in well. Add flour mixture alternately with milk and mix well. Add vanilla essence. Fold in nuts.
Bake in preheated oven for 35 to 40 minutes or until a toothpick inserted into the cake comes out clean.