It would be best to store your Lemon Blueberry Tiramisu in the refrigerator, covered with plastic wrap, or in an airtight container to prevent it from drying out or absorbing any other flavors in the refrigerator. It is best to chill the tiramisu overnight before serving, but it can also be stored in the fridge for up to 2-3 days if stored properly. It is not recommended to freeze Lemon Blueberry Tiramisu because the texture and taste of the dessert may be affected. The mascarpone cheese and whipped cream may separate and become grainy or watery after thawing. Additionally, the ladyfingers may become soggy and lose their texture when frozen and thawed. Enjoying this dessert fresh and within the recommended storage time frame is best.