01 - Preheat your oven to 425°F. Line a baking sheet with parchment paper.
02 - In a skillet over medium heat, cook the diced Chinese sausage for 2–3 minutes until fragrant and lightly browned. Drain excess fat and let cool.
03 - In a large bowl, whisk together flour, baking powder, baking soda, salt, and sugar.
04 - Add the cold, diced butter. Using a pastry cutter or your fingertips, cut the butter into the flour until the mixture resembles coarse crumbs.
05 - Stir in the cooled sausage, scallions, and sesame seeds.
06 - Pour in the cold milk and mix gently until a shaggy dough forms. Do not overmix.
07 - Turn the dough onto a lightly floured surface. Pat into a 1-inch thick rectangle. Fold the dough in half, pat out again, and repeat once more for flaky layers.
08 - Cut out rounds using a 2.5-inch biscuit cutter. Gather scraps and repeat, handling dough as little as possible.
09 - Place biscuits on prepared baking sheet, close together for softer sides or spaced for crispier edges. Brush tops with beaten egg for shine.
10 - Bake for 16–18 minutes, or until golden brown. Cool slightly before serving warm.