Banana Bread

1/2 cup softened butter or margarine 
1 cup granulated sugar 
2 eggs 
1 cup mashed ripe bananas (3 medium) 
2 cups flour 
1 teaspoon baking soda 
1/2 teaspoon baking powder 
1/2 teaspoon salt 
1 cup chopped walnuts 

Cream butter and sugar together. 
Add one egg at a time, beating till smooth. 
Blend in mashed bananas. 
In second bowl, stir flour with baking soda, baking powder, salt and nuts. 
Add to banana mixture stirring only to moisten. 
Transfer to greased loaf pan. 
Bake in 350 deg. F. oven for about 1 hour until inserted toothpick comes out clean.