For these easy fish sandwiches, we broil haddock fillets until tender and flaky. Haddock is lean and mild, so to boost flavor, we first season it with olive oil mixed with aromatic coriander and cumin. And to add richness, the toasted rolls are spread with a mixture of yogurt, tahini and additional spices. Leafy greens, sliced tomato, shaved red onion and fresh flat-leaf parsley are all delicious additions for these sandwiches.