On a cutting board, cut the castella into ¼-inch (6 mm) slices.
In a bowl, use a hand mixer to combine the heavy cream and sugar.
Add the Greek yogurt and blend until stiff peaks form.
Line a 7x7 inch (18x18 cm) bowl with plastic wrap and add the sliced kiwi to the bowl.
Add a layer of whipped cream to cover the kiwi. Place the castella on the cream.
Add half of the chopped orange and pineapple. Cover with a layer of whipped cream, and top with castella. Add the remaining half or orange and pineapple, top with whipped cream, and remaining castella.
Cover the top layer in plastic wrap, and refrigerate for 3 hours.
Place a plate on the opening of the bowl, and gently turn the bowl over, removing the plastic wrap.