I'd like to get the word out to as many southeast Asia-bound chowhounds as possible: go to Sumatra! We just spent two weeks on the island eating any and everything in sight. It was all wonderfully delicious, and made even more so by the vendors, stall operators, shop owners, and restaurateurs who fed us. In my experience, Sumatrans qualify as among the friendliest, most welcoming folks in Asia.
We didn't cover the whole island, or even a fraction of it; Sumatra is huge, distances are long, so if you're sticking to road travel, as we did, you won't see alot in 2 wks. No matter - what you don't accomplish in sightseeing you can make up for in eating!
Padang is a great place to start - a surprisingly laid-back city on the west coast. Here is the place to sample 'nasi padang', the "real" rijstaffel; up to 15 small plates are placed on your table as soon as you sit down. Sample curries of fish, beef, veggies (and calf brains, we heard, but never encountered in a spread) and veggies (young jackfruit is particularly wonderful) and pay only for what you eat. Our favorite spot in Padang was Pagi Sore (everyone knows where it is); the rendang (beef stewed in chili, coconut milk, and warm spices like cloves and cinammon), which is cooked for more than twelve hours, has set my new standard for this dish.
Also noteworthy in Padang: mie ayam ('chicken noodles'), sold by a mobile vendor on the bridge at dusk. Yellow noodles and Chinese greens are boiled together and placed in a bowl with a bit of boiling water. Two kinds of red chili sauce are added, and a blob of 'sambal hijau' (lit. 'green' sambal - hot and sour and garlicky), then a splash each of coconut oil and kecap manis, a large spoonful of savory and sweet slow-stewed chicken, a soy-cooked hardboiled egg, and a shower of small rice crackers. Once it's all mixed you end up with a sweet/spicy red-brown broth/sauce, fairly thin but thick enough to coat each strand of pasta. It sounds very basic, I know, but this noodle dish was so tasty that we diverted back to Padang ahead of schedule so we could experience another bowl before leaving Sumatra.
There is a v. small Chinatown in Padang and here you'll encounter bubur (rice porridge) to beat all rice porridges. Creamy plain congee is topped with a variation on the stewed chicken described above, chunks of century egg, broth/sauce from the chicken, pickled cabbage (some vendors), Chinese celery, and pieces of youtiao (Chinese crullers). Kecap manis and chili to be added at the table. Incredible depth of flavor. What a way to start the day. Mobile vendors (look for 'bubur ayam') and coffee shops on Jalan Pondok.
In Bukittingi, 'nasi Kapau' gives nasi Padang a run for its money (Kapau is a village in the area). The concept is the same (rice and many dishes) but it's served differently: rice is topped with a dab of sauce from several of the dishes, and then solids from the dishes of your choice - fish, veg, meat, whatever. These dishes are somehow more vibrant than most nasi Padang mains - spicier, more sour (tamarind is used in many of them), turmeric used in most. We liked Linda's Nasi Kapau in the market (there is a section devoted exclusively to nasi Kapau stalls) ... her explosive sambal hijau is soured with belimbing, a small green veg/fruit that looks a bit like a mini green starfruit.
One of our favorite breakfast foods was 'godok pisang' - deep-fried balls of dough that, depending on the vendor, resembles banana bread or a very chewy banana muffin. I don't often go in for deep-fried food, but one of these babies hot out of the frier, it's golden crispy exterior enclosing a dangerously hot, extremely banana-y interior, is the perfect accompaniment to a cup of 'kafe susu' (Sumatran coffee with sweetened condensed milk - specify 'sedikat susu' if you want to guarantee a propensity of coffee over sweet).
A healthy and guilt-free but very addictive sweet is 'putu pisang' (banana 'pancake') - a sourish variety of banana grilled till soft, then smashed between two pieces of wood. It's laid on a banana leaf and topped with freshly grated coconut on smoky palm sugar. Let the sugar melt a bit, roll up, and eat. The best of this treat we had at the BT market ... beware the ones proffered on the bridge in Padang - topped with a slick of margarine, coconut, white sugar, artificial-tasting chocolate sprinkles, and grated processed cheese food. We didn't want to offend the friendly vendor so managed to choke it down - but it was truly awful.
We encountered woefully few tourists - great for us, not so great for the locals; we were told Americans especially are a rarely sighted species these days. Sumatra is a goldmine for chowhounds, travel is no more difficult than, say, Vietnam, and it's very inexpensive. We ate with abandon and never suffered illness (this is an individual thing, I know - but by comparison I've been sick many times in Vietnam). If you plan to go take along a copy of "Eat Right in Indonesia" - almost all the food vocabulary you'll need is in there. We'll be heading back soon, if for no other reason than another bowl of those chicken noodles.
More details, with photos to follow in a week or so at link below.