Old Fashioned Chocolate Cake

3/4 cup butter or margarine
2/3 cup cocoa
1 2/3 cups sugar
1 1/4 tsp. baking soda
3 eggs
1/4 tsp. baking powder
1 tsp. vanilla
1 tsp. salt
2 cups flour
1 1/3 cup water

Combine butter, sugar, eggs and vanilla. Beat on high for 3 minutes. In separate bowl, combine flour, cocoa, baking soda, baking powder and salt. Add alternately to creamed mixture with water. Blend until just combined. Pour into greased and floured 9 inch layer pans or 13x9 pan. Bake at 350 F for 30 to 35 minutes, or until tester inserted in center comes out clean. Cool 10 minutes, remove from pan and cool completely.