In a large bowl, combine 600g flour, 20g warm milk, 7g active dry yeast, and 5g salt. Mix with 120g softened unsalted butter until a dough forms. Knead on a floured surface for 10 minutes until smooth. Let rise in a warm place for 60 minutes, covered with a tea towel.
Roll the dough into 14 equal portions. Flatten each into 200g discs. Place on a baking sheet and let expand for 30 minutes. Shape them into buns by pulling up the edges and pinching the seams closed.
Meanwhile, marinate 700g cubed chicken with 15g sambal oelek, 12g honey, 2g paprika, and a pinch of salt for 30 minutes. Dredge in cornstarch before deep-frying in sunflower oil at 180°C for 6-7 minutes until golden. Drain on paper towels.
Preheat oven to 200°C. In a small bowl, mix 15g sambal oelek with mayonnaise, Greek yogurt, and lemon juice. Brush half of the sauce onto the buns and top with a small mound of fried chicken. Sprinkle parmesan, cayenne pepper, and flaky salt on each bun.
Bake for 25 minutes until buns are golden and crisp. Finish by brushing the remaining sambal glaze on top and serve immediately.