When we just started with the solids, it went well. She loved her cereals.
But when veggies and meats came along, she chose her favorite ones, and was rejecting anything else. At some point just to let her eat, i will mix banana with any of her lunches. Yikes, i know! So it was chicken with sweet potato and banana, or peas with fish and banana.
I even mixed broccoli (which she hates) with banana, yet it worked like a charm. Of course it wasn’t for long. And i have to come up with something new. But it should work with your little ones for a while until the novelty runs out and they find a new challenge for you.