Mix dry ingredients together: nuts, baking powder, salt and flour.
Beat 1 cup softened butter then add half of the sugar and 1 tsp vanilla. Keep beating until creamy.
Add in 5 egg yolk, one at a time and continue beating.
In a separate bowl beat together egg whites until frothy.
Add in the rest of the sugar and 1 tsp vanilla extract. Beat together until fluffy and stiff.
Using a large spatula, fold in the fluffy egg whites into the batter.
With a spatula, add in the wet ingredients into the dry ingredients (nuts, flour and baking powder).
Put into the greased pan.
Bake for 50-60 minutes or until toothpick comes out clean.