Beat eggs in small mixer bowl; gradually add sugar and vanilla. Blend in melted butter; beat well. Combine flour, baking powder and salt, add to egg mixture. Remove 1 cup batter, stir nuts and maple flavoring into it. Add cocoa to the batter remaining in bowl; blend until combined.
Spread batters in alternate 2 inch wide rows in greased 8 inch square pan. Zigzag a rubber spatula or scraper through the batter lightly, being careful not to blend too well. Bake at 350 degrees for 30 to 35 minutes or until brownies begin to pull away from edges of pan. Cool in pan. Cut in squares. Makes 16 brownies.
