♥I've seen a few different versions of notecards using a butterfly punch, and here is my take on it. My photos turned out so dark (boo!), but hopefully you can see my stitching...
I have a package of pre-cut cards with envelopes that I used ~ sewed a line with a loop in the middle and up through the center of the butterfly. I like how they turned out and will be making more, for sure.