Because this is a small and little developed tourist destination, the restaurants don't think about serving tourists. There just haven't been many coming to Sen Monorom. And with the locals usually eating at home, the restaurants don't stock much food. The procedure here is to go one our before to the restaurant you would like to eat and tell them what you would like to eat. You can leave then, while they go to the market to buy the ingredients and return to the restaurant to prepare the dishes. An alternative would be to stop by in the morning and tell them what you want for lunch or evening meal. It's certainly not the norm at destinations around Cambodia, but here it seems to work out okay. Anyhow there are more restaurants opening during the last 2 years, which serve mostly Khmer or Vietnamese food. You might ask them to combine something for a more European style.
Chom Nor Mondulkiri restaurant is the biggest in town and serving asian and european foods.
It's actually the oldest accommodation place in Sen Monorom serving their guests also fresh, tasty and reasonable dishes. It's located east from the market next to the street leading to the centre.
It's also next to the street leading to the centre, but a bit further away. They have a small restaurant offering quite common Khmer dishes.
Arun Reah 2 Guesthouse.
This guesthouse is 1,5km far from the centre on the main road, which goes to Snoul. It covers also a small restaurant offering a limited menu.
There isn't a name, but it's easy to find. It's a very simple place, but they do a good job concerning the food and they have drinks with ice. The prices are very reasonable. It's right next to the centres round about (two buffalos).
There are two restaurants near the entrance area to the market. They double as community entertainment centers; local residents gather outside to gaze at videos on the TV screens inside. They can also serve the necessary karaoke hall function.
If you're eager to have some real European food made by a European you'll need to visit the Bananas. The wodden house next to a tiny creek is owned by a German woman named Tanja. She is a cook and cooks on request. The dishes are real good and quite reasonable. It's situated down the hill from the centre and then left before you pass the bridge.