Janus - You seem to have a daughter in the same mould as mine. DD is now 23 mths, and things have improved a little - she eats more variety now, but getting it in is still a struggle.
You will, I am sure, have seen the looks of 'but she must be eating something', and 'I don't really believe you' when you try to recount your fears re the amount and/or variety of food that she will eat. I kept a food chart when my dd was under the paediatrician, and often it contained 1/2 fish finger, 1 chicken O etc (that's per day I hasten to add!) I too thought that perhaps I did the wrong thing in not giving jars.
I can only say to cheer you that they really can survive on very little, and don't succumb to letting her eat rubbish just so that something goes in. My HV suggested puddings to fatten her up! Or was that so she got up the centiles and didn't become such a worry?
I got through by continually trying different things - not at every mealtime, but every couple of days. I know that my dd became very suspicious of food in general, even when it was familiar.
I don't have any brilliant food tips to offer, except that I bought an ice-cream maker. Dd will eat ice cream, and when I make a fruit ice-cream with a custard base (fruit, eggs and cream, very little sugar if any), I know she's eating something good for her.
Also, after discovering that she would eat cheese on toast, she now gets cheese mixed with poached salmon, or tuna, or ham, and/or mushrooms, peppers, onions etc (soften in frying pan or microwave first), and mix with a little mayo. I basically have become the master of disguising food.
Sorry to go on, but I really know what you are going through. I just hope that your dd improves with age. Good luck!