In a saucepan, add all syrup ingredients. Heat over medium heat until simmering and the sugar has dissolved. Pour the syrup through a sieve into a bowl to cool down.
In a stand mixer with a whisk attachment (or you can use a hand mixer and a large bowl), beat the heavy cream, mascarpone cheese, powdered sugar, freeze-dried strawberry powder, and vanilla extract until stiff peaks form. Be careful to not overwhip the cream!
Dip each ladyfinger in the cooled syrup for a few seconds, making sure they are completely coated but not soggy.
Arrange a layer of soaked ladyfingers in the bottom of an 8x8-inch dish (20x20 cm).
Spread half of the cream mixture over the ladyfingers.
Repeat the process with another layer of soaked ladyfingers and the remaining cream mixture.
Cover the top of the dish with plastic wrap or a large plate and refrigerate for at least 4 hours (or overnight) to allow the flavors to meld and the cream to set.
Just before serving, decorate the top with thinly-sliced, fresh strawberries. Cut into 9 squares and serve.