First off, the marshmallows are better the 2nd day. Still not something I would make again but yeah, I can see why if stored in a large jar and aged somewhat they'd be attractive to some people. A little firmer. Not crunchy, but concentrated. Not so fluffy. Dryer. They'd be more interesting with rose flavoring or something more pronounced than vanilla.
This was the first cover.
This was the second.
They both have their strengths and weaknesses. And I am 51% for the 2nd.
I won't name names but I've seen covers obviously designed by the writer (far more famous than I) that I didn't think were all that strong graphically and they still sell. So I say this to encourage you to give creating your own cover a whirl. Don't set the bar so high you pre-fail. You can buy a perfectly good image for a ridiculously small amount of money and use the basic design I've used with this cover. Split the cover in 3rds. Image in the middle. Name on top, title on bottom. Title on top, name on bottom. Use a common font. Don't be too creative. Don't do drop shadows or outline. Keep it simple. You might be more successful than you imagine.