With firm, white flesh and a mild flavor, tilapia pairs well with many vegetables, spices, and sauces. This farmed fish is commonly sold as frozen, deboned, skinned fillets. Frozen fillets don't absorb the flavor of marinades and rubs as well as thawed fillets, but they can still be cooked properly.
Defrosting Frozen Fillets
To safely defrost tilapia fillets, place them in a bowl, cover, and leave in the fridge overnight. If you don't have time for this, place the fillets in plastic ziplock bag and submerge the bag in a bowl of cold water. (Do not use warm water as this creates an environment friendly to bacteria.) You can also defrost fillets using a microwave's defrost setting.
Cooking Thawed Fillets
You can bake, grill, or fry thawed tilapia in a hot pan (the hotter the pan, the crispier the fish). Thawed fillets can be marinated or seasoned with a dry rub prior to cooking. Put the fillets in a sealable plastic bag along with the marinade or rub and let sit in the fridge for 20 minutes to an hour. A marinade penetrates the flesh faster than a dry rub.
Cooking Frozen Fillets
If you don't have time to defrost, fillets can be poached, steamed, baked, broiled, or grilled from frozen. They can't be marinated prior to cooking, but you can always add a flavorful sauce during or after cooking. First, rinse them under running water to remove any frost, and then pat them dry. Cook the fillets until they're done—the flesh should be firm but not rock hard and should flake easily with a fork.
Freezing Fresh Fillets
To freeze fresh fillets, pat the tilapia dry and wrap it in plastic wrap, or place it in a heavy-duty freezer bag. If using plastic wrap, wrap the fillets in a double layer, either individually or in pairs. Freeze them in small batches, as they cannot be frozen again after defrosting and may spoil if you can't use them all at once. Make sure the plastic wrap or freezer bag touches the fillets directly with no air bubbles, which can lead to oxidation. An airtight seal also minimizes the chance of freezer burn. Fish can typically be frozen for at least two to three months, and longer if well-packaged and kept in a very cold freezer.