I always have consistency issues with my curry. My ratios are off or something. It doesn't end up tasting authentic. My last batch of Dal Tadka tasted too fruity for some reason, and I can never get that savory umami type flavor that you get with real curry bases.
I've found that pureeing the veggies (onion, tomato, chili) can help thicken the sauce. The slower solution is to cook down the dal more, though that may be undesirable if you don't want them pasty. For chickpeas, smash a dozen or two and stir them into the masala.
"Fruity" could mean you didn't cook the tomatoes enough; the sweetness is tempered with umami with time. Cooking the tomatoes longer also releases the pectin, thickening the sauce. Too much of some of the sweeter spices like fennel, anise, cloves, or cardamom could be interpreted as fruity, though I'd say they're more of a flowery sweetness.
Great answer. It's really easy to underestimate how long to cook down the onions and tomatoes to get the right flavour profile. I know it took me a while to get down.
Yes! Amchoor powder (dried young and green mango) is used in northern indian dishes to give it the umami flavour. Tamarind is usually used in the south.
Usually used along with or in place of tomatoes, so you'll get a less fruity flavour. If you can get some to try out in your Indian recipes, I highly recommend!
No problem, both these ingredients are really underrepresented in Euro-Indian recipes, but are pretty essential in India itself! I only learned about them from my best friend's grandmother.