How to Make It
In a medium bowl, combine the 1 tablespoon of salt with 2 cups of hot water and stir to dissolve the salt. Let cool to room temperature, then add the fish to the bowl and let brine at room temperature for 30 minutes.
Meanwhile, in a small bowl, whisk the oil with the butter, lemon juice, miso and garlic until smooth; season with salt.
Preheat the oven to 450°. Line a baking sheet with parchment paper. Drain the fish and transfer to the prepared baking sheet; brush all over with the lemon-garlic butter. Roast until golden and just cooked through, about 10 minutes for the salmon and 15 minutes for the hake. Transfer to plates, garnish with sesame seeds and serve with lemon wedges.