@FrozenpeaceWe can really only make suggestions here as to how the conversation was interpreted by each party, however I’d say this.
He possibly asked the question already having a series of “acceptable answers” stored in his brain. Who knows what these were, but they may have been things like food items, things that involved unpacking, things that had a specific Easter theme or things that could be done in the same space as where he and the kids were opening/eating the eggs.
When you said flowers he might have very well thought that it was fine, he’d get you flowers, but shoved that aside for now because you hadn’t provided an acceptable answer based on his predictions, therefore he sorted the dilemma by deciding to get a bigger egg.
This might have served a duel purpose.
One, you would possibly eat a small piece and this would be perceived as a positive because you were fulfilling, in his mind, the set requirements of Easter, and two, he would have more chocolate available to him, which he likes.
You haven’t done anything wrong, and in his mind, neither has he. After giving you the possibility to choose a suitable alternative he has found a solution to what is a known problem for some people, ie feeling left out. He identified that you might feel this, and gave you the chance to rectify it.
If you would enjoy the flowers, then tell him that you would like them, but I wouldn’t insist that they are a solution to the egg situation😆