Butter sole (Isopsetta isolepis) is a flatfish in the righteye flounder family, Pleuronectidae; despite the common name, it is not a true sole (family Soleidae). It gets its name from its delicate, tender texture and mild, faintly sweet flavor, sometimes likened to the richness of butter.
Butter sole is native to the northeastern Pacific, ranging from the Bering Sea and the Aleutian Islands along the coasts of Alaska and Canada down to central California. It is caught commercially along the U.S. and Canadian Pacific coast and typically sold, often simply labeled 'sole,' through West Coast fish markets.
In the kitchen, butter sole is prized for its versatility. The thin, flat fillets are well-suited for a variety of cooking methods, including pan-frying, baking, poaching, and grilling. The delicate texture of the fish means it cooks quickly and requires gentle handling to prevent it from falling apart. Butter sole pairs well with simple seasonings, such as lemon, parsley, and butter, allowing its natural flavors to shine.
Butter sole should not be confused with the unrelated European lemon sole (Microstomus kitt), which shares a similar-sounding name, or with true soles of the family Soleidae, such as Dover sole; the Atlantic and European culinary traditions built around those fish, such as sole meunière or bouillabaisse, are not traditions associated with this Pacific species.
In terms of practical applications, butter sole is a versatile ingredient that can be used in a wide range of dishes. It is a popular choice for light, healthy meals, as the fish is low in fat and high in protein. The fillets can be baked, pan-fried, or poached and served with a variety of accompaniments, such as roasted vegetables, salads, or rice.