Heat oven to 350°F. Place paper baking cup in each of 24 regular-size muffin cups.
In large bowl, beat cupcake ingredients with electric mixer on low speed 30 seconds. Beat on medium speed 2 minutes, scraping bowl occasionally. Divide batter evenly among muffin cups.
Bake 18 to 20 minutes or until toothpick inserted in center comes out clean. Cool 10 minutes; remove from pans to cooling racks. Cool completely, about 30 minutes.
In 2-quart saucepan, heat brown sugar, whipping cream and butter to boiling over medium heat, stirring constantly. Boil 1 minute. Remove from heat. Add powdered sugar; stir with wooden spoon until spreadable. Frost cupcakes. Sprinkle with 1/2 teaspoon apple pie spice.