Spoon 1/3 cup frosting into a resealable plastic bag and set aside. Tint remaining frosting pale yellow. Stack two cakes, with yellow frosting in between and on top. Measure in 1 inch from edge of third layer, and cut wedges off layer to create lower slope of roof. Place trimmed third layer on top of stacked cakes. From the last layer, cut 1 inch off opposite sides of cake, leaving a 6-inch wide piece of cake. From center, cut a wedge off each side to bottom edge, creating the upper slope of the pointed roof. Stack last trimmed layer on top, using yellow frosting to secure.