Niuean food is rooted in Pacific staples: taro, breadfruit, cassava, fresh fish, shellfish, and coconut. The star ingredient is uga — coconut crab — a large land crab with sweet, rich meat. It's a genuine delicacy and Niueans are proud of it. You'll find it at the market, at Lilo's restaurant, and occasionally at the Crazy Uga Café. Don't leave without trying it.
Other dishes worth seeking out: ota ika (raw fish marinated in citrus and coconut milk, similar to ceviche), takihi (layers of taro and pumpkin cooked in coconut cream in an earth oven), and freshly caught mahi mahi or tuna prepared simply.
Most of Niue's restaurants are in Alofi. The choice is small but covers the basics. Hio Beach Café, run from a converted shipping container at Hio Beach, has become well-known for its fish tacos and relaxed atmosphere. Manuiz hosts a Wednesday night umu buffet — a good way to try a spread of traditional Niuean cooking. Crazy Uga Café does proper espresso, which is harder to find than you'd expect.
Sunday is worth flagging: most restaurants are closed. Stock up on supplies before the weekend if you're self-catering, or check your accommodation's arrangements.
The Alofi market (Tuesday, Wednesday, Friday mornings) is the best place to find local fruit, vegetables, and sometimes coconut crab. Get there early.