Traditionally, you do not have to ferment an adai batter. That's the charm of it in the first place. You can set the beans and rice to soak, and slap that bad boy onto the griddle immediately. I prefer my crepes a little more fermented, because I like the flavour better, so I decided to ferment. You may choose not to. The choice is yours.
I personally prefer it with the mix that I've come up with. You can actually alter the mix to your own likes and dislikes. If you don't have toor daal, use moong daal. If you don't have either, use split peas, and it'll get you there. The essential part is that you make it with at least equal parts lentil to rice.
Unlike dosa, Adai is not so popular for a couple of reasons. For one thing, it's more expensive by a long shot. Traditional dosa calls for a 4 parts rice to 1 part urad daal mixture. This means that if you buy the cheapest rice, and the urad daal on sale, you can generally knock out a batch for a family of six with very little money. Adai, on the other hand, calls for much higher quantities of lentils. In my version, there are even more lentils than rice!
For another thing, because of the heft and "stuff" found inside of adai, it's not as popular with the kids, who like the diaphanous and crispy dosa, because they don't have much chewing of little bits to get through, and they can easily eat a couple and feel comfortable. An adai, on the other hand, is filling. It tends to be one of those things that you can have one, maybe two of at the most. Because it's so nutritionally dense, you tend to feel full faster, and stay full much longer than if you were to eat a dosa.
Finally, it's not as amenable to being folded over. It's a hefty little crepe. You can't fold it easily like you can a dosa. It doesn't take to fillings so much as it takes to the stuff already folded into the batter.
All that being said, if you don't mind the extra expense of making adai, you will be greatly rewarded. For one thing, it's much easier to handle the batter grinding. Unlike dosa, you need not grind the rice and beans down to a fine puree. You can get away with a bit of grit in the batter. You can also add all kinds of different things to the batter, and still turn out OK. You can sub out part of the rice for oats, or buckwheat, or even millet and still turn out something that's very tasty. You can sub out the daal for actual whole beans, like mung beans or chickpeas, and it'll still be delicious.
You can also fold in an endless variety of add-ons into the batter. Adai batter is extremely forgiving. You have some leftover chopped onions from the main dish you were making? In it goes! You have some extra grated carrots from the salad? Throw it in! You like to boost up the nutrition value by adding ground flax seed (as I did in this recipe; flax seed isn't traditional, but it's most delicious)? The batter will be better! The sky's the limit with regards to the flavouring options.
Add to this the fact that you can serve it with any kind of sauce (mint, cilantro, tamarind-date), chatni (coconut, mango, tomato), or stew (sambhar, rasam, kootu)/vegetable (curry, poriyal) that your brain can think of, and you're talking about a very useful little dish to have on hand.
Bear in mind that I did this to suit my tastes, and you may want to leave out the optional ingredients. Don't worry. I won't be offended! I personally like the addition of the urad daal, because it helps to keep the batter stronger and more coherent. I like the flax seed, because it means that I can thicken the batter after grinding with plenty of water. My blender isn't very powerful, so I need to add extra water to get it all ground down to my liking.
For the batter:
1 1/2 cups brown rice
1 1/2 cups toor daal
1/2 cup urad daal (OPTIONAL)
1 TB fenugreek seed (OPTIONAL)
4 cups water
Soak the ingredients for the batter for 3 hours. If you're adding fenugreek seed, and using brown rice, like I am, soak it for 6 hours, and you'll end up with better results. If you're using urad daal, like I am, please only soak the urad daal for about an hour.
Then, after the soaking process is done, add the mixture into the blender, in 1 cup increments, with about 1 cup of soaking liquid at a time. The reason to go in small batches is so that you don't strain your blender. We're not in a rush here, and this recipe makes a large batch of batter.
At the end of the blending, you'll end up with a batter like the one pictured above.
At this point, if you're using the fenugreek seed, take the batter and set it into a container on your countertop to ferment overnight. If you're not bothering with the fenugreek, don't bother to ferment. The fermentation step is strictly because I like the taste of it, and because I wanted adai for breakfast the next day, and not dinner that night.
When you're ready to fry off the adai on your skillet, you can add in your additions.
Additions:
1 1/2 cups chopped onion
1/2 cup chopped ginger
1/4 cup chopped curry leaf
3 green chilies (OPTIONAL)
2 - 3 pinches of asafoetida (OPTIONAL, if not using onion)
1/4 cup flax seed (OPTIONAL)
Any other veg you'd like
Mix the additions into 4 cups of batter, and salt to taste. Grind the flax seeds in a coffee grinder until it's a powder. Stir it into your batter. You'll have a cup or two of leftover batter to use later. The batter will be very thick and should bubble a little bit if you fermented it overnight. If you need to, thin it out with a bit of water. You want it to resemble a thick and chunky pancake batter.
Because I didn't go shopping this week, I didn't have much in the way of additions. I wish I had some coconut to fold in. That would have been lovely. I just added the ginger, onion, and curry leaf.
Using a 1-cup ladle, pour the batter onto a hot skillet (heated over medium high heat), and spread the batter around in concentric circles until it's about 1/4 inch thick. Don't worry about getting it crepe thin. It's never going to be super thin, because of the add-ins. This is OK. I'm using a nonstick skillet, so that I don't have to add very much fat.
Using a squeeze bottle, or a small spoon, put a few drops onto the perimeter of your adai.
When to Flip?
Look at the picture of the adai after it's sat on the skillet for about 30 seconds (click the image if you want a larger version). Notice how most of the surface looks mostly translucent? Notice how some of the "peaks" look a much more opaque white colour? The opaque bits (that I've circled in the image) are still not cooked all the way through. You want the bottom of the adai to be browned, and the top to be almost completely cooked before turning. At this point, I've still got too many uncooked bits, so I'm not going to turn it over yet.
Finally, once the adai is mostly cooked on the side you can see, flip it over, and look at the other side:
Isn't that beautiful? Flip it over a couple of more times until it's browned to your liking, then serve.
