post from 2010 that shows me making homemade uncrustable style PB& J sandwiches using a wine glass. The things I can come up with when working with just what I have in my kitchen! Hey, it worked. They looked just like the ones you buy in the box. A couple of years and many wine glass made sandwiches later I was in a grocery store and noticed a interesting square shaped plastic thingy hanging on the shelf. As I got closer I noticed the Wonder logo and something on the small tag that told me what it was. I was pretty excited about finding it. Definitely because it did what I was doing in a quicker fashion but also because it was like $3. Maybe $4 but either way it was affordable. I haven't looked back since. And because we took a long break from making this style of PB& J's, the kids didn't think twice about it being a square not a circle.
If you run across one of these, I would recommend getting it. It is less expensive than the other one I saw here and it hasn't let me down yet. I hand wash it but it's dishwasher safe. A couple of things to remember is not to overfill your sandwich. It will make sealing it tough or you can end up with a rip in the bread. A standard size/shape piece of bread fits perfectly. The more rectangle pieces as well as the kind of small pieces of bread don't always work. I make up four to six at a time, put them in a freezer bag with a piece of parchment or wax paper between them and throw in the freezer. Easy, easy.