This is Simplicity 7335, which was released in 1967. I bought it from this etsy seller.
I initially felt a little self-conscious in this--it feels huge! But I've come around to it and actually think it's pretty cute. Plus, it feels like wearing a nightie! Bonus.
The construction was super easy. The bodice is lined (with the lightweight siri lining from my shop) and has armhole facings. The box pleat in the front has a pleat underlay.
The hardest part was getting the bow to look right. It's just a bias piece tied into a bow but it took a lot of fiddling with.
I never thought I'd wear something like this, but I like it! Change is good, right?