Arctic Char Tostadas
Chef Daniela Soto-Innes thinks of these as a Mexican take on bagels with cream cheese and lox. The addictive caramelized fish sauce vinaigrette brightens every bite.
- 1 cup unseasoned rice vinegar
- 1 ½" piece ginger, peeled, finely grated
- ¼ tsp. finely grated lemon zest
- ½ cup farmer’s cheese or whole-milk ricotta
- 1 8-oz. boneless arctic char or salmon fillet
- Extra-virgin olive oil (for drizzling)
- Cilantro leaves with tender stems, sliced serrano chiles, capers, and lime wedges (for serving)
Heat a small saucepan over medium. When hot, pour in 1 Tbsp. fish sauce. It should bubble up vigorously and then get thicker and slightly darker, about 30 seconds. Repeat with remaining fish sauce, incorporating 1 Tbsp. at a time. Carefully add vinegar (it may spatter), then transfer mixture to a small bowl; let cool. Stir in scallions and ginger. Taste and season with salt.
Do Ahead: Vinaigrette can be made 1 week ahead. Cover and chill.
Preheat oven to 300°. Mix lemon zest into cheese in a small bowl; season with salt and set aside. Place fish on a rimmed baking sheet and drizzle very lightly with oil; season with salt. Bake until just opaque throughout, about 5 minutes for char and 8–10 minutes for salmon. Remove from oven and break apart into large flakes. Drizzle with ¼ cup Salty-Sour Vinaigrette.
Divide reserved cheese mixture among tostadas. Top with fish, then cilantro, chiles, and capers. Serve with lime wedges.