In most cases, the smaller the cake, the easier it will be to cover with rolled fondant. However, there is an easy way to position and smooth fondant on cakes that are 12 in. diameter or larger. Follow the steps shown to lift fondant onto the cake without tearing.
Cover cake with buttercream icing. Roll out fondant sized to your cake.
Slide a large cake circle that has been dusted with confectioner's sugar under the rolled fondant. Lift the circle and the fondant and position over cake. Gently shake the circle to slide the fondant off the board and into position on the cake. Smooth and trim fondant.