Blend oil or melted butter, sugar, and vanilla in a large mixing bowl. Add eggs, using a spoon, beat well. Combine flour, cocoa, baking powder and salt. Gradually blend into egg mixture. Stir in nuts. Spread in greased 9 inch square pan. Bake at 350 for 20-25 minutes or until brownies begin to pull away from the edges of the pan. Cool, frost, cut into squares
Frosting: 1 1/2 Cups powdered sugar, 1 tsp. vanilla, 1 cube butter or margarine softened, 1/4 cut unsweetened cocoa, add can milk until proper consistency.