Lots of parents - me included! - get into bad habits with food because we are so worried about the kids not eating enough and it will never end until you decide not to do it. Don't start, is my advice.

I'm assuming she's well and growing ok? If so, just keep offering what you're happy for her to have, let her feed herself - it's important developmentally for all sorts of reasons - and everything will fall into place. They don't need a lot of food at this age, their growth rate has slowed compared to the first 12 months. It's normal for 2 year olds to eat significantly less than 1 year olds for this reason.
Looking at intake over a week is very good advice! They have eating days and non eating days, they get a bit of this one day, and a bit of that another, but overall it all works out.
It's ok to offer different things - you don't have to be a total hardarse - but keep offering, calmly and without a hint that you care either way.
If you don't allow them to make a mess they won't learn how to do it properly. It's mess now or feeding them and cleaning up after them for a lot longer.