To prepare lotus root: Peel and slice the lotus root thinly. Bring water to boil and turn off heat. Add the lotus root slices and calamansi lime juice. Cover with lid and set aside for 3 minutes; drain in a colander.
Heat the oil over medium heat and fry the lotus root for 2-3 minutes; remove and set aside.
To stir-fry: To the oil remaining in the wok, add the sesame oil. Heat the oil and add the garlic; stir-fry until fragrant or lightly browned. Add the lotus seeds, gingko nuts and sauce ingredients and bring to a boil.
Add the medlar seeds, fried lotus slices and macadamia nuts. Add the corn flour mixture and bring to boil. Adjust seasonings to taste and remove the heat. Transfer to a serving platter and serve immediately.