1Grease 13" x 9" pan. In medium bowl combine cocoa and baking soda. Blend in 1/3 cup melted butter. Add boiling water; stir until mixture thickens. It thickens quickly. Stir in sugar, eggs and remaining 1/3 cup melted butter; stir until smooth.
2Add flour, vanilla and salt; blend completely. Stir in chocolate chips. Pour into pan.
3Bake at 350 degrees for 35 to 40 minutes or 30 to 35 minutes in 2 8" x 8" pans. Cool. Frost if desired.