1Heat oven to 350°F. Place paper baking cup in each of 18 regular-size muffin cups. In large bowl, mix flour, granulated sugar, cocoa, baking soda and salt. In medium bowl, mix buttermilk, oil, 1 teaspoon of the vanilla and the egg with whisk until blended. Add oil mixture to flour mixture, stirring just until blended. Divide batter evenly among muffin cups.
2Bake 18 to 20 minutes or until toothpick inserted in center comes out clean. Cool 5 minutes; remove from pans to cooling rack. Cool completely.
3In large bowl, beat butter, 1 cup of the powdered sugar and remaining 1 teaspoon vanilla with electric mixer on medium speed until smooth. Gradually add remaining powdered sugar, beating until blended. Frost cupcakes. For each cupcake, place small spider-shaped stencil or template on frosting; sprinkle black sanding sugar over stencil to cover the image. Carefully remove stencil. Place red candy in center of spider.