One of the interesting aspects of working with edible flowers is the question of ‘what does edible mean, exactly?’ There are lots of plants where if you consume a large amount, it may make you ill, but a few petals won’t hurt you at all.
I’m not a doctor, or an herbal expert, so generally if you see me using flowers in cooking, please don’t take it as an assurance that you can just go ahead and cook with them willy-nilly — do your own research! And please take extra care if you’re pregnant.
But all that said, a few petals of mountain bluet (centaurea montana), considered an astringent herb, are lovely on a lime & rosewater shortbread cookie, and according to Texas A&M University, the flowers are edible. I think you’d be safe scattering a few petals in a salad as well. I wouldn’t make a stir-fry from the plant, though!
“An astringent herb, its flowers have been used as an ingredient for eye ailments such as conjunctivitis and corneal ulcers as well as for minor wounds and ulcers of the mouth. Flowers are edible. Extracts of the plant are used in shampoos and conditioners. Dry flowers for pot pourris. Centaurea is named for Chiron, a centaur known for his herb knowledge and who first introduced Centaurea as a healing plant.”
https://aggie-hort.tamu.edu/…/pla…/Centaureamontana.html
Recipe here: https://serendibkitchen.com/…/lime-rosewater…/