Brownies

1 cup (2 sticks) butter or margarine
2 cups sugar
2 tsp. vanilla
4 eggs
3/4 cup cocoa
1 cup flour
1/2 tsp. baking powder
1/4 tsp. salt
1 cup chopped nuts
 
Grease 13 x 9 inch cake pan.  Microwave butter in large bowl until melted.  Stir in sugar and vanilla.  Add eggs, one at a time, beating well with spoon after each addition.  Add cocoa; beat well.  Add flour, baking powder, and salt; beat well.  Stir in nuts.  Pour batter into prepared pan.  Bake at 350 degrees for 30 to 35 minutes or until brownies begin to pull away from sides of pan.   Cool.  Cut into bars