Saucy, Tangy Slow-Roast Sambal Salmon
Step 1
Place a rack in middle of oven; preheat to 300°. Place 1½ lb. skin-on, boneless salmon fillet, scales removed, skin side down in 2½-qt. baking dish (it should be just big enough to hold fish). Rub flesh side of salmon all over with 1 Tbsp. vegetable oil, then 1 Tbsp. finely grated lime zest and 2 tsp. Diamond Crystal or 1¼ tsp.Morton kosher salt (you want it to be evenly seasoned). Roast until salmon is barely cooked in the center and flesh flakes when gently pressed with a spoon, 20–30 minutes.
Step 2
Ten minutes before salmon is done roasting, whisk 2 Tbsp. dark or light brown sugar, 2 Tbsp. sambal oelek, 2 tsp. cornstarch, and ⅔ cup room-temperature water in a small bowl until sugar is dissolved; set sauce aside.
Step 3
Heat remaining 2 Tbsp. vegetable oil in a large nonstick skillet over medium-high. Cook 1 small white onion, cut through root end into ½”-thick wedges, tossing often, until lightly blistered in spots, 5–7 minutes. Add 6 cloves garlic, finely chopped, and one 1″ piece ginger, peeled, finely chopped; cook, stirring constantly, until fragrant, about 1 minute. Add 1 large red bell pepper, halved, ribs and seeds removed, thinly sliced, and cook, stirring constantly, until peppers just start to soften, about 4 minutes.
Step 4
Pour reserved sauce (whisk well first to dissolve settled cornstarch) over vegetables and cook, stirring often, until sauce thickens and clings to vegetables, about 3 minutes. Remove from heat and , stir in 2 Tbsp. fresh lime juice and 1 Tbsp. toasted sesame oil.
Step 5
Pour sauce over salmon in baking dish. Scatter 2 scallions, thinly sliced, on top. Serve with cooked white rice or noodles alongside. (Spoon salmon into large pieces, leaving skin behind, when plating.)