Cold Poached Salmon with Miso Mayonnaise
4 cups / 1 L water
5- to 6-inch / 12 to 15 cm square piece dried kelp (konbu)
½ onion, sliced
6 slices ginger
¼ tsp / 1 mL salt
⅓ cup / 75 mL dried bonito flakes
1 lb / 500 g salmon fillet, skin-on
3 thin slices lemon with peel (seeds removed)
Radish (red or daikon) and/or cucumber slices (optional)
1½ tbsp / 22 mL mirin
1 tbsp / 15 mL white miso
1 tbsp / 15 mL lemon juice
1 tsp / 5 mL rice vinegar
⅓ cup / 75 mL mayonnaise
2 tbsp / 30 mL cooled salmon poaching liquid
¼ to ½ tsp / 1 to 2 mL Japanese hot pepper powder (togarashi or shichimi), optional
Bring water, kelp, onion, ginger and salt to boil; cover and simmer for 15 minutes; remove from heat and add bonito flakes. Let sit covered for 5 minutes. Strain into saucepan just large enough to hold salmon lying flat.
Return liquid to boil; add salmon, skin-side down, reduce heat to just under a simmer and lay lemon slices over fillet; cover and poach until salmon is just cooked through, still slightly translucent in center of thickest part (check by separating a flake in center of fillet with point of sharp knife), 10 to 13 minutes. Remove salmon and lemon slices from liquid and let cool. Spoon out scant 2 tbsp/ 30 mL of liquid; set aside and let cool to be added to the sauce. (Let remaining liquid cool; refrigerate or freeze for use in as a soup base, e.g. miso soup, or a broth base for soup noodles or Japanese-style sauces for seafood.
Miso Mayonnaise: In smallest saucepan, bring mirin to boil; light mirin with flame and remove from heat. Whisk in miso, then whisk in lemon juice and vinegar. Let cool. Whisk miso mixture into mayonnaise. Whisk in reserved poaching liquid; add hot pepper powder to taste, if using. Refrigerate until cold.
To finish: Remove skin from salmon and plate over and/or surrounded by watercress, red radish or daikon and/or cucumber slices as desired. Place lemon slices decoratively over salmon. Serve with Miso Mayonnaise.