Olive-oil poached salmon are served over lemony pea stew with pistachios, and a celery-root puree.
Heat oil in an 8-quart heavy-bottomed pot over low heat until it registers 140 degrees on a deep-fry thermometer. Add thyme and garlic to oil.
Season fillets with salt and pepper. Carefully add to oil; cook 5 minutes. (Adjust heat as necessary to keep oil temperature at 140 degrees.) Flip; cook 5 minutes (for rare) or 7 minutes (for medium-rare). Transfer to paper towels; pat dry.
Divide pea stew among bowls; place 1 fillet in center of each. Season with fleur de sel (or other coarse salt). Garnish with nuts, and with lemon confit if desired.