In a large bowl, stir the olive oil, lemon zest, garlic, ginger, turmeric, salt, and paprika until a paste forms.

Add the cod fillets and turn to coat them well. Let them marinate until you are ready to use them.

Lightly crush the cumin seeds. In a large heatproof bowl, combine the cumin and oil.

Microwave in 30-second increments, stirring each time, until fragrant and warmed through, about 1 to 3 minutes. Let it cool slightly.

Add the lemon juice and honey, then season with salt and pepper. Stir to combine.

Add the cabbage, cilantro, carrot, and onion; toss to coat them well and refrigerate until you are ready to use the slaw.

Finely grate the cucumber and squeeze out any excess liquid.

In a medium bowl, combine the cucumber, yogurt, garlic, and lemon zest. Season with salt and pepper, then stir to mix well.

Prepare a grill for medium-high heat and preheat for 5 minutes.

Lightly brush the cut sides of the buns with olive oil. Grill the buns cut side down until warmed and charred, about 1 to 3 minutes.

Grill the marinated cod, turning halfway through cooking, until it’s cooked through and an instant-read thermometer registers 145°F. This usually takes about 2 to 5 minutes per side, depending on the thickness of the fillets.

To assemble, spread tzatziki on the bottom half of each bun. Top with grilled cod and slaw, then close with the top half of the buns.