You can use spices and herbs, just avoid salt (and salty things like soy sauce or Worcestershire sauce etc). Mine was prob around 8 months when I made some potato wedges (skins on, baked in the oven) with garam masala seasoning sprinkled over them. He LOVED them, however within 1 min of starting to eat his hands, wrists, and face came up in a blotchy skin rash, everywhere the garam masala had touched he reacted. I gave him a thorough wash as fast as I could and didn't offer any more of that food, waited the rest of the day watching for any sickness but he was fine, it was only an external reaction. I must admit i avoided that particular spice mix for a long time after but he is just one LO, I am sure heaps of LOs are fine with it. He loves curry and now he is older even helps me cook curry for the family.
So, yes I think some babies do like strong flavours and have taste for certain groups of foods too, mine loves carrots, sweet pot, courgette, aubergine, capsicum, green beans, mange tout, asparagus...but will not eat cauliflower, cabbage, broccoli. I often hear many kids like broccoli, I think they have a taste for it or they don't. Either way, offering the same food many many times will eventually lead to a taste of it. I found it helped mine to have foods cut into the same shape as he recognised them this way.