Fish Tacos with Preserved Grapefruit Salsa

Using a sharp knife, remove peel and white pith from grapefruit. Working over a medium bowl, cut grapefruit segments from their surrounding membranes, dropping them into the bowl; discard the membranes and any seeds. Add avocado, shallot, cilantro, preserved grapefruit paste and 1 tablespoon oil; toss to combine.

Heat a large cast-iron skillet over high heat. Add the remaining 1 tablespoon oil and heat until shimmering. Season fish on both sides with salt and pepper. Add to the pan and cook until lightly browned and starting to flake, 2 to 3 minutes per side, depending on thickness.

Serve the fish, salsa and cabbage in tortillas.