There is no restaurant scene here, and pretending otherwise would be dishonest: you eat what the guesthouse kitchen cooks, plus whatever the mainland market sent over that morning.
Nakasang market
The mainland market by the boat pier, and the reason anything on the islands has ingredients. It runs early, roughly dawn to mid-morning, and sells river fish, sticky rice, herbs, fruit and grilled snacks. Worth an hour on the day you arrive or leave, and far cheaper than anything served on Don Det.
Guesthouse kitchens on Don Det and Don Khon
Almost every place to stay is also a restaurant, and the menus are near identical: fried rice, noodle soup, Mekong fish, curries and a long backpacker section of pancakes and sandwiches. Food comes slowly because it is cooked from scratch by one person, so order and then order the beer.
Mok pa and laap pa
The two dishes worth asking for by name: mok pa is river fish with herbs and chilli steamed in a banana leaf parcel, laap pa is minced fish with lime, mint and toasted rice. Both come with a basket of sticky rice you eat with your right hand. Say bo phet if you genuinely do not want chilli.
Lao coffee and the baguette
Coffee comes down from the Bolaven Plateau three hours north and is served short, strong and poured over condensed milk; ask for it black as kafe dam. The other colonial leftover is the baguette, split and filled, sold from carts in Nakasang and at breakfast on the islands.