Brush the pineapple thoroughly under running water. Trim the leaves and cut 1/3 lengthways from the pineapple. Level the opposite side so that the pineapple comes to rest firmly. Hollow out with a sharp spoon and make sure that there is at least 1 cm of wall everywhere. Squeeze all pieces except for 60g pulp in the slow juicer. Use the juice for the sauce.
Cut the beef fillet into thin slices across the grain. Chop larger pieces into bite-sized pieces. Mix with the sesame oil and keep ready.
Clean the mushrooms and generously separate the nutrient substrate with the mushroom mycelium at the bottom. Separate the mushroom stalks close to the hat and chop crosswise, leave the hats on. Chop the pineapple pieces into bite-sized pieces. Cap the onions and the cloves of garlic at both ends, peel and roughly cut into pieces. Wash the small, green chillies and cut them crosswise into thin slices. Leave the grains and discard the stems.
Wash the fresh kailan, separate the leaves from the stem. Cut off the woody stem below the 2nd leaf and discard. Separate the thin petioles from the leaves along the midrib, cutting the leaves in half lengthways. Cut the leaf stalks and the stem crosswise into thin rolls. Roughly cut the leaves into small pieces. Keep leaves and stalk rolls ready separately. Freeze unused goods. Measure and defrost frozen goods.
Wash the fresh celery, remove the stems and the defective leaves. Roughly chop the leaves and prepare them. Weigh frozen goods and allow to thaw. Wash the peppers, remove the stem, cut open lengthways, unfold, core, cut across into thin strips and cut them across into small cubes.
For the sauce, dissolve the tapioca flour in the rice wine, then add the remaining ingredients and mix until homogeneous.
Heat the frying oil in a wok or deep fryer to 180 degrees. Roll the pieces of meat in plenty of tapioca flour and let them slide into the frying oil in portions. Use a slotted spoon to make sure that the pieces stay separate. Fry until light brown. Drain on paper towels and keep ready.
Remove the deep-frying oil from the wok, add the sunflower oil and let it warm up. Add the onion and garlic pieces and stir-fry until the onions are translucent. Add the pineapple pieces and stir-fry for 2 minutes. Add the chillies, the kailan stalks, the mushrooms and the chili peppers and stir-fry for 2 minutes.
Deglaze with the sauce, mix in the leaves (from the kailan and celery) and the meat, season with salt and pepper. Pour into the pineapple, serve warm with white rice and enjoy.