Run 7 ounces of water (about 200 ml) into the saucepan, then top it off with a splash of broth or stock. Make sure you use enough liquid to completely cover the fillets. Add your choice of aromatics, such as lemon slices, whole peppercorns, bay leaves, and allspice.  For a tangier poaching liquid, you can also use white wine in place of the broth or stock. Traditionally, a mixture of diced onion, carrots, and celery known as “mirepoix” is also incorporated into the poaching liquid. These ingredients can be useful for infusing your hake with a subtle savory flavor. Place the saucepan on the cooktop over medium-high heat until it just begins to bubble. Allow the mixture to simmer for 2-3 minutes. This will give the various flavors a chance to mingle.  For best results, your poaching liquid should reach a temperature between 160–180 °F (71–82 °C) before you add the hake.  Be careful not to let the liquid come to a full boil. High heat can cause the tender fish to disintegrate. Lower the fillets carefully to prevent splashing. They should lie flat against the cooking surface and be completely submerged. If you haven’t used quite enough liquid, pour in additional water, wine, broth or stock until the fillets are covered. If you run out of room in the pan, it may be necessary to cook the fish in batches. The hot poaching liquid will quickly cook the hake through without drying it out. Keep an eye on the fillets in the meantime. When the meat turns opaque and takes on a plump, juicy appearance, they’re ready to come out.  Avoid stirring the fillets as they’re poaching. Handling them too much could cause them to fall apart. Poaching is one of the fastest ways to prepare lighter types of fish like hake. Remove the fillets from the saucepan using a slotted spoon to strain the excess liquid. Place the fillets on a layer of folded paper towels to soak up any remaining moisture, then transfer them to individual plates for serving. Poached hake goes particularly well with bright, mild vegetables like tomatoes, mushrooms, and zucchini.  Some buttery dinner rolls or a loaf of crusty, fresh-baked bread can help balance out the moistness of the fish nicely. Poach fish is best enjoyed fresh. However, any uneaten portions should keep for 2-3 days in the refrigerator when stored along with the remaining poaching liquid.
Fill a deep saucepan with 2–3 inches (5.1–7.6 cm) of poaching liquid. Heat the poaching liquid to a low boil. Add the hake fillets to the pan in a single layer. Stew the fillets for 10 minutes. Drain and serve the hake.