1. Heat oven to 350°F. Line muffin cups (2-1/2 inches in diameter) with paper bake cups.
2. Stir together dry ingredients in large bowl. Add shortening, buttermilk, water, eggs and vanilla. Beat on low speed of electric mixer 30 seconds, scraping bowl constantly. Beat on high speed 3 minutes, scraping bowl occasionally.
3. Fill muffin cups 1/2 full with batter. Bake 20 minutes or until wooden pick inserted in center comes out clean. Remove from pan to wire rack. Cool completely.
4. Prepare PEANUT BUTTER CREAM FILLING; place into pastry bag fitted with large star tip. Insert tip into center of cupcakes; pipe filling into cake. Remove tip from cake; garnish top with swirl of filling. Decorate with candies, if desired. Cover; refrigerate leftover cupcakes. About 3 dozen cupcakes.
* To sour milk: Use 2-1/4 teaspoons white vinegar plus milk to equal 3/4 cup.
PEANUT BUTTER CREAM FILLING
2 packages (3 oz. each) cream cheese, softened
2/3 cup REESE'S Creamy Peanut Butter
1/4 cup milk
1 teaspoon vanilla extract
3 cups powdered sugar
Beat cream cheese and peanut butter in large bowl until blended. Add milk and vanilla; beat well. Gradually add powdered sugar, beating until smooth. Add additional milk, 1 teaspoon at a time, if necessary, until desired consistency. About 2-3/4 cups filling.