To prepare the pork, place all char siu pork ingredients except the pork butt in a large bowl and whisk until combined. Then place the marinade and pork in a large resealable plastic bag.

Massage the outside of the bag to work the marinade over all parts of the pork, then place the bag in the refrigerator for at least 3 hours and up to 12 hours.

When the pork is marinated, add 1 cup of water to the pot. Place the bottom layer of the Deluxe Reversible Rack in the higher position, then place in the pot. Remove the pork from the marinade and place on the rack.

Close lid and move slider to PRESSURE. Make sure the pressure release valve is in the SEAL position. The temperature will default to HIGH, which is the correct setting. Set time to 25 minutes. Select START/STOP to begin cooking.

While the pork is cooking, prepare the dough. Add the milk, butter, yeast, and sugar into a medium sized bowl and whisk until combined.

Allow the mixture to sit and let the yeast activate for 5 to 10 minutes, until the mixture is bubbling and frothy.

Add the remaining dough ingredients into the bowl, mixing by hand until fully combined.

Transfer dough onto a clean flat work service and knead until the dough is smooth and stretchable, about 10 minutes. Test the dough by pulling a piece of it using both hands. It should stretch into a very thin and translucent sheet. While kneading the dough, grease the inside of a bowl that will fit inside the Ninja Foodi XL pot with a thin layer of butter or oil.

Pull the dough into a tight ball using your hands and place it into the greased bowl. Flip the dough ball a couple of times so that it is fully coated in the butter.

When the pork is complete, manually release pressure by turning valve to VENT position. Move slider to AIR FRY/STOVETOP. Select AIR FRY, set temperature to 400°F, and set time to 12 minutes. Select START/STOP to begin cooking.

After 6 minutes, open lid and turn pork halfway through cooking to brown evenly on all sides.

When cooking is complete, remove the pork from the pot and allow to cool before cutting.

Clean the inside of the pot, then add ¼ cup of water.

Place bottom layer of Deluxe Reversable Rack in the lower position, then place in the pot.

Add dough in oiled bowl, uncovered, on rack over water in Ninja Foodi XL.

Close lid. Select PROOF, set temperature to 95°F, and set time to 30 minutes. Press START/STOP to begin the rise.

When the rise is complete, remove the basket from the pot.

To make the filling, discard any remaining water in the pot. Select SEAR/SAUTÉ and set to HI-5.

Add water, sugar, soy sauce, rice wine, oyster sauce, hoisin, and sesame oil to the pot and bring to a simmer.

Whisk in the cornstarch and water mixture and whisk until thick, about 1 minute. Select START/STOP to stop cooking. Stir in green onions and chopped pork.

Allow mixture to cool before assembling buns.

Turn dough onto lightly floured surface, press down on dough to deflate.

Place the bottom layer of the deluxe reversible rack in pot on lower setting. Place 8 inch round of parchment paper on rack.

Divide dough into 7x 2 ounce portions (approximately golf ball size), roll each into tight balls and keep covered with plastic wrap.

Flatten each dough ball into 4 inch diameter, thinner at the edges. Fill each with 2 tablespoons of filling and carefully bring edges up over filling, taking care to keep filling away from edges. Pinch to seal tightly.

Place balls, pinched seam side down, all around the edges and in the center of the parchment paper on deluxe reversible rack. Balls should not be touching at this point.

Using a pastry brush, brush dough balls with egg wash and sprinkle with sesame seeds.

Close lid and move slider to STEAM & CRISP, set temperature to 335° and set time to 10 minutes.

Press START/STOP to begin cooking.

When cooking is complete, brush buns with sugar syrup.

Serve warm, garnish with additional green onions if desired.