Place the sugar in a small sauce pan, add enough water for it to resemble wet sand. Place over medium-high heat and bring up to a bubble, simmer until the sugar has dissolved in the water. Remove from the heat and add the limoncello, let it cool while you prepare the cake and filling.
In a bowl combine the lemon zest, ricotta cheese and the honey. Cut the angel food cake into 3 slices horizontally; make sure the slices are of equal thickness so that you end up with 3 doughnut looking slices of the same thickness. Arrange the bottom slice on a serving plate. With a pastry brush drench the slice with 1/3 of the limoncello mixture, top the slice with a 1/2 of the ricotta cheese mixture, repeat with the next layer and finish the top with the last 1/3 of the limoncello mixture.