Preheat oven to 160 degrees C. Grease one 20 or 25cm ring cake tin. Mix together the flour, bicarb soda and salt. Set aside.
In a large bowl, beat butter with sugar. Mix in the eggs, one at time, beating well after each addition. Stir in the lemon and the vanilla essences. Gently mix in flour mixture alternately with the buttermilk. Pour batter into the prepared pan.
Bake in preheated oven for 90 minutes. Do not open oven door until after one hour. When cake begins to pull away from the side of the pan it is done. Let cool in pan for 10 minutes, then turn out onto a wire rack and cool completely.