With warm slices of pork, creamy Hoisin sauce, and cold / crisp cucumbers, these sandwiches got great reviews for their layers of texture and flavor when this meal was last featured in March 2020. Smarts: The pork in this recipe makes enough for 2 nights. Set half aside for Thursday's fried rice.
Make marinade - Crush garlic cloves with the palm of your hand. Discard peels. Combine garlic cloves, pineapple juice, soy sauce, oil (first portion for Char Siu), and Chinese five spice. (Can be done up to 5 days ahead)
Marinate pork - Combine pork with marinade. Turn to coat. Tenderize with a fork. Marinate for at least 30 minutes and up to 2 days. (Can be done 2 days ahead)
Make Hoisin mayonnaise - Combine mayonnaise, Hoisin sauce (portion for sandwiches), and chili garlic sauce. (Can be done up to 5 days ahead)
Broccolini - Trim broccolini. (Can be done up to 5 days ahead)
Remove pork from marinade (discard marinade). Pat pork dry and season generously with some salt and pepper.
Heat a large oven-safe skillet with oil (second portion for Char Siu) over medium-high heat. Add pork and sear on all sides until golden brown, 10 to 12 minutes total.
While pork sears, toss broccolini with cooking oil (portion for broccolini), toasted sesame oil, sesame seeds, and some salt.
When pork is seared on all sides, remove pan from heat. Pour stock into skillet. Add broccolini to skillet, nestling it around the pork. Spoon Hoisin sauce (portion for pork) over the top of the pork.
Transfer skillet to the oven and roast until pork is cooked (reaches an internal temperature of 145F / 63C), 25 to 45 minutes. Broccolini should be done cooking after about 25 minutes. If it finishes cooking before pork, remove it from the pan and set it aside, covered to keep warm. (Note: Cook time for the pork will vary depending on thickness. If using pork tenderloin, these are typically much smaller and will cook faster. Start checking pork tenderloin after 12 minutes in the oven. If pork tenderloin finishes before broccolini, remove pork and allow broccolini to continue roasting.)
Transfer pork to a cutting board and let rest, covered, for 7 minutes.
Move broccolini to a serving plate. Reserve pan juices from the bottom of the skillet.
Squeeze lime juice over broccolini.
Slice pork and drizzle reserved pan juices over the slices. (Reserve half the pork for Thursday.)
Toast buns.
Assemble sandwiches by filling buns with Hoisin mayonnaise, green onions, pork slices, and cucumbers. Serve with broccolini on the side.
To get a head start for Thursday, dice the portion of pork for that night's meal.