Opening up the back of the mittens to get them on little hands

I'm sick of trying to get mittens on my toddler! It's so hard to try to shove his hand in and make sure his thumb ends up in the thumb spot. I'm sure I've seen some place a mitten where you can open up the back to lay the child's hand in, then fold it back over and velcro it down to keep it in place. Can you picture it? I could try to draw a picture of what I mean . . . It seems like it ought to be relatively straightforward to draft this, but I can't find a pattern like this or a tutorial to adjust a pattern. Has anyone ever seen such a mitten pattern? Thanks!