In a mixing bowl, combine lukewarm water, milk, honey, and instant yeast, letting it sit for 5 minutes until bubbly. Mix in the beaten egg and sunflower oil, then gradually add all-purpose flour, salt, and butter. Knead the dough on a floured surface for 10-12 minutes until smooth and elastic. Place the dough in a greased bowl, cover it, and let it rise in a warm spot for 1 hour or until doubled in size.

While the dough rises, cut the chicken fillet into small pieces and transfer them to a mixing bowl. Add salt, onion powder, garlic powder, cayenne powder, black pepper, sambal oelek, soy sauce, and the beaten egg. Mix thoroughly until all ingredients are well combined. Cover the mixture and refrigerate for at least 1-2 hours.

Once the dough has risen, gently deflate it and divide it into 14 equal pieces, each weighing about 70g. Roll each piece into a ball, then flatten it into a rectangle. Fold the rectangle in half, brush the top with milk, and dip it in the Parmesan topping mixture. Arrange shaped buns on a baking sheet lined with parchment paper and let them rise for another 30 minutes.

Preheat your oven to 200℃ (392°F). Once the buns have risen, bake them for 12-15 minutes or until they are golden brown.

In a mixing bowl, combine cornstarch, salt, black pepper, and onion powder. Coat the marinated chicken pieces in the cornstarch mixture. Heat oil in a frying pan over medium heat until it reaches 175℃ (350°F). Fry the coated chicken pieces in batches for 5-7 minutes or until golden brown and crisp. Drain on paper towels.

In a small bowl, whisk together mayonnaise, chili sauce, and sambal oelek to create a creamy sauce. Adjust heat and sweetness to your preference.

Fill each baked bun with a generous portion of fried chicken. Drizzle the prepared sauce over the chicken filling, adding fresh vegetables if desired.