Pour the cream into a bowl of a standing mixer. Using the whisk attachment, whip the cream until soft peaks form. Add the sugar, mascarpone or sour cream and salt then whip until the cream becomes pretty stiff. Detach the bowl from the stand mixer and fold 1/2 cup of the lemon curd into the cream with a rubber spatula. Just give it a few big folds so that the curd is swirled into the cream but not fully mixed.
Put the cream into a piping bag fitted with a tip or large zip-top bag. If using a zip-top bag, cut off one of the corners.
Break a few gingerbread man cookies into the bottom of a 9- or 10-inch sprigform pan to form one flat layer. Using your piping bag, pipe 1/4 of the cream mixture on top of the gingerbread man pieces. Place 10 to 12 gingerbread man cookies upright along the perimeter of the pan so they look like they’re holding hands around the cake pan. Add another layer of broken gingerbread man cookies and another 1/4 of the lemon cream. Repeat two more times, ending with a final layer of lemon cream on top.
Cover the pan with plastic wrap and refrigerate overnight.
Garnish with a few more gingerbread man cookies; slice and serve.