Normally Bombay rava takes (if, well roasted) 1 3/4 - 2 cups of water & wheat rava takes 2 1/2 - 3 cups of water . As soon as you buy rava , roast it dry on a pan , on medium heat till very well roasted & keep . This way, roasting to be done when you make upma , is minimum.
1 cup of bombay rava needs 1 3/4 - 2 cups water.
1 cup wheat rava needs 2 3/4 - 3 cup. All this , assuming that you have roasted the rava very well.(this is the key point )
( wheat rava upma is given in tips)
Next is oil .Perfect upma requires correct amount of oil - in fact a tsp more makes the upma very soft & nice. That is why upma served in restaurants & weddings is so delicious - they are not bothered to be stingy about oil , because they want to give the best taste .
For 1 cup B.rava - keep 2 cups of boiling water ready . (i don't add cold water to hot rava because lumps are sure to form!) . In a vessel , heat (bare minimum) 2 tbsp of oil, temper mustard seeds , 1 tsp udad dhal , 1 tsp gram dhal ,2 chopped onions , 4, 5 chopped green chillies & 1” ginger chopped , curry leaves & fry till onions are transparent. Now add the (pre roasted )rava & continue to roast on a medium flame till the rava gets well heated. Now decrease the flame , add 1 3/4 cups boiling water, stirring well ( I find a whisk useful ) , add salt & hing. You will now know whether you need to add 1/4 cup more of water or not. Mix thoroughly , lower the gas & wait till the entire water is absorbed & the rava is cooked. Mix once again & keep covered - rest for a few mts. Now some people add a tsp of ghee as topping to give a good flavour - this is optional.
In Chennai , I find that all branded ravas take 2 cups of water. But always keep rava very well roasted & the roasting to be done with other ingredients when making upma should be minimum.
Vegetable rava upma:
Carrot, beans, potatoes, cauliflower can be chopped fine , lightly steamed & added when you add water.
Capsicum can be finely chopped & added after you do the tempering, sauted & then the rava added.
Boiled peas & corns can be added.
For a change, without adding onions or vegetables, add 2 tbsp grated coconut after switching off to give a different taste.
Variations:
To give a slightly sour taste, lime juice can be added after switching off & thoroughly mixed. I now add amchur powder, when I add boiling water & that is an interesting variation! Both these can be omitted also, if you don’t like a sour taste.