Prepare the duck one day in advance. Remove giblets and slice off the duck neck and excess fat from the duck cavity. Discard or save for another use. Lightly prick the duck all over with a knife or cake tester (piercing skin but not the flesh), then make diagonal scores starting from the top of the duck breast down to the legs, again taking care not to slice all the way through the flesh. (At this point your duck can be refrigerated for up to 7 days—or just proceed to next step.)

Up to 24 hours before you roast, mix 1 tablespoon of Momofuku Tingly Seasoned Salt and ½ tablespoon of cinnamon. Rub the seasoning mix all over the duck and inside the cavity and refrigerate for 4 hours and up to 24 hours to allow the skin to dry out.

Heat the oven to 425°F and allow the duck to come to room temperature (about an hour). Arrange sliced oranges and onions in a layer on the bottom of your sheet pan—this will keep the duck fat from splattering as it cooks. Drizzle with 1 tablespoon of olive oil. Place duck, breast side up, directly on oranges and roast for 30 minutes.

Meanwhile, prepare your glaze. Add honey, Momofuku Soy Sauce, 1 teaspoon of Momofuku Tingly Seasoned Salt, and ½ teaspoon of cinnamon to a small pot and bring to a slight simmer. Cook on low for 3-4 minutes until just thickened, taking extra care not to allow it to boil as it will burn. Set aside.

Remove the duck from the oven and carefully empty any jus from the duck cavity into a small bowl, reserving for later. Return the duck to your sheet pan, brush all over with glaze, and return to the oven for 10 minutes.

Mix broccolini with olive oil and 1 teaspoon of Momofuku Tingly Seasoned Salt in a large bowl and toss to combine. Set aside.

Remove duck, brush with glaze again, and arrange broccolini around the duck. Roast 10 more minutes. Remove, brush with glaze one last time and roast until the internal temperature of the thigh reaches 155°F, about 10 more minutes.

For a rare duck breast, roast the whole duck for 20 minutes to start, then start glazing every 10 minutes, and remove your duck when the breast reaches 130°F. Slice off legs, return to pan, and continue to roast until they reach 155°F (about 10 more minutes).

Let the duck rest for 5 minutes before carving and serving. Save jus from carving. Mix a teaspoon or 2 of the duck jus with the remaining glaze and serve as a sauce on the side.