Drain the pineapple and set the juice aside (you'll use it to soak the ladyfingers).

Line a glass bowl with plastic wrap (if you don't have a zuccotto mold), then arrange the pineapple slices to cover the inside of the bowl or mold. Decorate each pineapple slice with a candied cherry. Cover with more plastic wrap, press gently with your hands, and refrigerate for at least 1 hour.

Soak the gelatin sheets in cold water.

Whip the heavy cream until stiff peaks form and set aside.

In a large bowl, combine the yogurt and mascarpone. Use an electric mixer to blend for a few minutes, then gently fold in the whipped cream.

Chop any leftover pineapple slices into small pieces and fold them into the filling with a spatula.

In a small saucepan, combine the limoncello and well-drained gelatin. Heat and stir until the gelatin is completely dissolved, then add to the filling mixture.

Remove the bowl with the pineapple from the fridge. Pour in half of the filling and smooth it out with a spatula or the back of a spoon. Dip the ladyfingers in the reserved pineapple juice and arrange them over the filling to cover the surface.

Pour in the remaining filling and top again with ladyfingers dipped in pineapple juice.

Cover tightly with plastic wrap and refrigerate for at least 6 hours, or freeze for at least 4 hours.

NOTE: If you froze the dessert, take it out at least 30 minutes before serving. If you just refrigerated it, a few minutes at room temperature is enough before serving.