1. Cook sweet potatoes for 20 minutes. Remove rosemary leaves from stem, starting about an inch down from the top. Cut the branches diagonally. Chop a quarter of the needles finely and mix with 4 tablespoons of honey.
2. Cut the chilli lengthwise and scrape out the seeds. Chop the chilli finely and stir into the rosemary-honey mixture. Set aside. Peel the pineapple and cut out the stalk. First cut the pineapple into slices about 1.5 cm thick and then into pieces. Pluck the mint leaves from the stalks and chop coarsely. Mix yoghurt, mint and 2 tablespoons honey.
3. Drain the sweet potatoes, leave to cool and peel. Cut sweet potatoes into cubes and place alternately with the pineapple pieces on the prepared rosemary skewers. Coat the grill with oil. Grill the skewers all around for 4-6 minutes. After grilling spread with honey marinade. Serve with mint sauce.
Preparation time: ca. 45 minutes