100 g satsuma mandarin juice, freshly squeezed
85 g butter, soft
50 g sugar, including 2 TB vanilla sugar
125 g flour
10 g cornstarch
1 pinch of salt
Bring the satsuma juice to a boil and simmer until its reduced to a quarter and syrupy. Let cool.
Whisk butter and sugar until creamy. Add the satsuma syrup (about 2 1/2 TB) and stir well. Add flour, cornstarch and salt, mix to incorporate. Don't be surprised, dough will be very soft. Shape into a log, wrap in foil and refrigerate at least 3 hours or overnight.
Cut into thin slices (3-5 mm), place on a baking tray lined with parchment paper. Bake in preheated oven at 175 deg C for about 12 minutes. Note: Cookies won't turn golden.
(Recipe adapted from Technicolor Kitchen)