To make the strawberry filling
Mix together strawberry pie filling and strawberry jam. Set aside.
To make the syrup
In a saucepan, bring lemon juice, sugar, vanilla extract and rum to a boil, stirring until the sugar has dissolved.
To make the lemon custard
Combine all of the lemon custard ingredients in a medium size sauce pan. Bring to a boil, over medium heat by stirring constantly with a whisk until the mixture thickens. Then immediately set the bowl in an ice water bath and let cool, stirring occasionally, about 10 minutes.
To make the mascarpone cream
In a large mixing bowl, either using an electric hand mixer or a stand mixer beat together all of the mascarpone cream ingredients at a medium-high speed until the mixture is smooth and thick.
Mix together lemon custard and mascarpone cream.
To assembly the charlotte
Use a 26 cm / 10-inche spring form pan.
Cut each cookie into 7-cm (2 ¾-inches) long pieces. The smaller pieces will be used to line the bottom of the pan. Quickly dip the smaller cookie pieces in the syrup and cover the bottom of the pan. Repeat the soaking with the long cookie pieces and place them upright along the inner walls of the pan. Then evenly spread over half of the creamy lemon mixture. Repeat with another layer of soaked ladyfingers continue with the strawberry filling and then top with the remaining creamy lemon mixture. Gently cover the pan with a plastic wrap and refrigerate for at least 8 hours or overnight.
When fully chilled and completely set, decorate with fresh strawberries, remove the sides of the spring form pan from the cake, and serve.
