Blend the plain yoghurt with the sugar using the bamix® multi-purpose blade and set aside. Prepare 6 glasses. Cut the fresh mango or defrost the frozen mango. Blend 400 g of the mango with 2 tsp lemon juice using the bamix® multi-purpose blade. Cut the remaining 200 g of mango into cubes. Alternate layers of the mango purée and plain yoghurt in the glasses, starting with mango purée and finishing with yoghurt. Place the mango cubes on top of the crème. Use the mint to garnish. Refrigerate the glasses until serving.