Instant Pot Glazed and Grilled Ribs

Mix mustard powder, garlic powder, sugar, and salt in a medium bowl to combine. Pat ribs dry with paper towels and arrange on a large rimmed baking sheet. Season ribs on both sides with all of dry rub, patting it on if needed. Cover with parchment paper or loosely with plastic wrap. Chill at least 1 hour or up to 2 days.

Pour mirin into Instant Pot. Place ribs in pot, orienting them on narrow sides so they’re leaning against walls of pot and each other (rather than stacking them flat, one on top of the other). Lock on lid, making sure steam release valve is in the proper sealed position. Select “Manual” and program for 9 minutes at high pressure. Let pressure release naturally 10 minutes, then manually release pressure. Unlock lid and transfer ribs to a rimmed baking sheet. Let sit at room temperature until ready to serve.

Do Ahead: Ribs can be cooked 1 day ahead. Let cool; cover and chill.

Prepare a grill for medium-high heat. Clean and oil grate. Pour cooking liquid from Instant Pot through a fine-mesh sieve into a medium measuring glass (keep sieve handy, you’ll need it again). Using a spoon, skim off excess fat from surface (you should have about 1¼ cups cooking liquid after skimming).

Pour cooking liquid into a large skillet. Add vinegar, Sriracha, fish sauce, and sugar and stir to combine. Add ginger, then bring mixture to a boil. Cook, swirling pan occasionally, until liquid is reduced by half, 7–8 minutes. Strain glaze through reserved sieve back into measuring glass and set close to grill.

Rub a little bit of oil on ribs to lightly coat. Grill ribs, meaty side down, until lightly browned, about 2 minutes. Turn ribs, generously brush glaze onto exposed side, and grill until underside is lightly browned, about 2 minutes. Turn ribs again and brush with glaze. Continue to grill, turning and brushing with glaze every 2 minutes, until ribs are dark brown and nicely lacquered on both sides with some charred spots, about 5 minutes total (smaller end of rack will be done first).

As they finish cooking, transfer ribs to same rimmed baking sheet and brush immediately with glaze. Let cool 5–10 minutes before cutting into individual ribs. Serve with any remaining glaze drizzled over; season with salt, if needed.