In a large mixing bowl, combine the softened mascarpone with the sifted powdered sugar using a spatula or whisk until smooth and creamy, about 2 minutes. In a separate bowl, whip the chilled heavy cream with an electric mixer on medium-high speed until soft peaks form, approximately 3-5 minutes. Gently fold the whipped cream into the mascarpone mixture until fully incorporated.

In a shallow dish, mix the freshly squeezed orange juice with half of the orange liqueur, stirring well to combine. Set the dish aside to allow the flavors to meld.

Take your ladyfingers and quickly dip each one into the orange juice mixture, ensuring they are moistened but not soggy. Arrange the dipped ladyfingers in a single layer at the bottom of a 9x13-inch serving dish. Spread half of the creamy mascarpone filling over the ladyfingers, followed by half of the strawberry preserves and half of the sliced strawberries.

Repeat the layering process with the remaining ingredients: another layer of dipped ladyfingers, the rest of the creamy mascarpone filling, followed by the remaining strawberry preserves and sliced strawberries. Finish with the last layer of cream on top, smoothing it out.

Cover the dish tightly and refrigerate the Strawberry Tiramisu for at least 2 hours, though overnight is best.

When ready to serve, remove the Strawberry Tiramisu from the fridge. Dust the top with powdered sugar or garnish with additional fresh strawberries if desired. Cut into squares and enjoy!