In advance: Tint sugar for tower peaks, door and window frames. For peaks, combine 8 oz. sparkling sugar with rose icing color in sandwich bag; seal bag and rub between hands to evenly tint sugar.

For frames, combine 4 oz. sugar with violet and rose icing colors and tint as above. Set aside. Prepare towers to insert in cake.

To make 1 large, 4 medium and 4 small towers which will be inserted in cake more stable, attach plastic dowel rods, cut 1 in. shorter than height of cake, to bottom of towers. Stand tower upside down; attach cut dowel rod to base with melted candy. Refrigerate until firm.

Ice towers and peaks smooth in buttercream; immediately press white sugar on towers and rose sugar on peaks. Pipe a tip 3 line of icing around door and window pieces; immediately press violet sugar on lines. Let all dry.

Prepare 2-layer round cakes for stacked construction; prepare cakes for rolled fondant. Tint 72 oz. fondant blue; cover cake and smooth with Fondant Smoother. Roll out 48 oz. fondant 1/8 in. thick; cut an 18 in. diameter circle for overlay. Position 14 in. round pan or cake circle at center of circle; cut 14 in. piece with craft knife, making random drifts on edge, 1 1/2 in. deep.

Position on 14 in. cake; smooth with Fondant Smoother. Thin piping gel with water and brush on overlay and 8 in. cake; immediately press white sugar on surface. Roll 1/2 in. balls of blue fondant and attach for bottom border with damp brush.

Mark and cut holes for 1 large and 2 medium towers on 8 in. cake top. Position 8 in. cake on 14 in. cake; insert door on front. On 14 in. cake, mark and cut holes for 2 small towers in front, 2 medium towers on side and 2 small towers in back. Insert all towers. Attach windows and position rock candy.