Fairly easy to catch and blessed with great texture and delicious flavour, lake perch has long been a cherished ice fishing prize. It cooks in a flash under the oven broiler, and when stuffed into tortillas along with punchy pickled vegetables and creamy avocado sauce, you have the makings of a tasty taco night as a fitting reward for a long day on the ice.
Pickerel is a good alternative catch of the day here, but you can also source out halibut or ocean perch from the fishmonger for these tacos.
Warming tortillas makes them more flexible and prevents them from cracking and breaking. Using your stovetop, turn a gas or electric burner on high. Using tongs, glide one tortilla at a time over the burner for a few seconds, alternating sides, until it’s softened and beginning to darken in spots. Cover tortillas to keep warm. Or wrap a stack of tortillas in a slightly damp kitchen towel (or paper towel) and microwave on high for about 30 seconds.
Per serving:
Place vinegar, sugar, salt, and mustard seeds, if using, in heatproof bowl. Bring 1 cup (250 mL) water to a boil in saucepan or kettle. Add boiled water to bowl with vinegar and stir until sugar has dissolved. Stir in cabbage and red onion; cover and let stand for at least 2 hours at room temperature, or overnight in refrigerator.
Preheat oven broiler and set oven rack about 6 in (15 cm) from heating element. Grease heavy baking sheet and place perch on greased pan. Season perch with lime zest, salt, and black pepper, to taste. Broil fish until just cooked through in the middle, about 5 to 7 minutes. Remove perch from oven and gently break apart flesh.
Place sour cream, avocado, lime juice, cumin, cayenne, and pinch of salt in blender or food processor container and blend until smooth.
To serve, divide fish, pickled vegetables, and avocado cream among tortillas. Garnish with cilantro.