For the lemon mango tart, prepare a springform pan with a diameter of 23-25 cm. Place the Bastogne cookies in a food processor and blend until crumbly. Butter the springform pan.
Melt the butter in a saucepan, add the cookie crumbs and stir well. Pour everything into the springform pan, smooth it out and press it down firmly. Then place the springform pan in the refrigerator for at least 30 minutes.
Then soak the gelatin sheets in cold water for about 10 minutes. Pour the milk into a saucepan and heat. Squeeze the gelatine and add to the milk with the sugar and vanilla sugar.
Stir until the gelatin has dissolved. Pour everything into a large bowl to cool well. Then add the mascarpone, yogurt, lemon juice and lemon zest to the milk mixture and mix.
Pour into the springform pan and refrigerate overnight. The next day, soak the 2 gelatin sheets in cold water for about 10 minutes. Puree 400 g mango without juice. Take 1 tbsp of the puree and fill it into the shortbread cookie.
Heat 1 tablespoon of water in a saucepan, squeeze out the gelatin and dissolve it in the water. Add the mango puree, mix well and pour onto the tartlet.
Place the tartlet again in the refrigerator for about 2-3 hours. In the meantime, finely dice the remaining 200 g of mango. Shortly before serving, arrange the diced mango decoratively on the lemon mango tartlet and serve.