Heat oven to 375'F. Line muffin cups (2 1/2" in diameter) with paper bake cups. In medium bowl, stir together flour, sugar, cocoa, baking soda and salt. Add water, oil, vinegar and vanilla; beat with a whisk just until batter is mooth and ingredients are well blended. Fill muffin cups 2/3 full with batter. Bake 16-18 minutes or until wooden pick inserted in center comes out clean. Remove from pan ti wire rack. Cool completely. Frost as desired. Makes 18 cupcakes.