1. Heat oven to 350°F. Line cookie sheets with parchment paper.
2. Stir together cake mix, cocoa and salt in large mixing bowl. Add water, oil and eggs; beat thoroughly. Drop by rounded measuring teaspoon onto prepared cookie sheet.
3. Bake 7 to 9 minutes or until wooden pick inserted in center comes out clean. Immediately transfer parchment paper with cookies to wire rack. Cool completely.
4. Spread 1 teaspoon chocolate spread or peanut butter chocolate spread onto flat side of one cookie. Place flat side of another cookie on top. Repeat for all cookies. Makes about 6 dozen whoopie pies.