1/2 cup margarine 
1 cup sugar 
1 teaspoon vanilla 
2 eggs 
1/2 cup cocoa 
3/4 cup flour 
1/2 teaspoon salt 
1/2 teaspoon baking powder 
3/4 cup chopped nuts 

Cream margarine and sugar, add vanilla and eggs and beat until fluffy. Stir in cocoa, flour, salt and baking powder. Add chopped nuts. 

Spread in a lightly greased 8 x 8 (or 6 x 8 pan for thicker brownies). Bake in regular oven at 350 degrees  for 25 min. 

Convection oven: bake at 300 degrees for 25 min. 

Note: This is one half of the recipe I always used when the kids were home so this can easily be doubled and baked in a 9 x 13 pan.