1 ripe avocado
1 cup crema or plain low-fat or nonfat yogurt
2 tsp. plus 2 Tbs. fresh lime juice
1 1/4 tsp. ground cumin
1/2 tsp. salt, plus more, to taste
2 cups shredded savoy cabbage or green leaf lettuce
1/2 cup diced English cucumber
1/2 cup diced red bell pepper
1 1/2 Tbs. extra-virgin olive oil
1 serrano chili, seeded and minced
3 Tbs. chopped fresh cilantro
2 Tbs. minced onion
1 lb. halibut or other firm-fleshed white fish fillet, skin removed
Freshly ground pepper, to taste
8 corn tortillas
Halve and pit the avocado and scoop the flesh into a food processor.
Add the crema, the 2 tsp. lime juice, 3/4 tsp. of the cumin and 1/4 tsp. of the salt.
Blend just until smooth. Transfer the crema to a bowl, cover and refrigerate for up to 2 days.
In a large bowl, combine the cabbage, cucumber, bell pepper, the 2 Tbs. lime juice, 1 Tbs. of the olive oil, the chili, cilantro, onion, the remaining 1/2 tsp. cumin and the remaining 1/4 tsp. salt. Stir to mix well.
Cover the slaw and refrigerate for 1 to 6 hours.
Prepare a hot fire in a grill and oil the grill rack. ??Place the fish on a plate and coat lightly with the remaining 1/2 Tbs. olive oil. Season lightly on both sides with salt and pepper.
Grill the fish, carefully turning it over once with a wide spatula, until opaque in the center, 6 to 8 minutes total.
Transfer the fish to a platter, break into 8 pieces and cover loosely with aluminum foil. Wrap the tortillas in foil and warm on the grill, about 5 minutes.
To assemble the tacos, place 2 tortillas on a plate and top each with a piece of fish. Stir the cabbage slaw well and top each piece of fish with about 1/4 cup slaw and 2 Tbs. crema.
Repeat to assemble the remaining tacos. Serve immediately. Serves 4