Set tiers on foam board; spread with thin coat of buttercream to seal in crumbs; chill until set, about 30 minutes. Apply final coat of buttercream.Advertisement
Insert dowels 2 1/2 inches from edge and 2 1/2 inches apart in all but top tier. Place bottom tier on cake board atop a nonslip mat. Add other tiers, using frosting to secure. Refrigerate until well chilled.
Cut 8-inch-long ribbon; fold ends into center; hot-glue. Cut 2-inch-long ribbon; wrap around center of bow, and hot-glue at back. Repeat to make four. Cut remaining ribbon to 17, 24, 30, and 37 inches; glue bow to center of each.
Let cake stand at room temperature 30 minutes, to allow buttercream to soften so the fruit straws will adhere better. Starting at back, press the fruit straws into the buttercream. Add ribbons.