Knit-Flat beanie pattern in stockinette stitch?

I’m having a REALLY hard time finding a beanie that is knit flat that won’t look boxy when seamed up. I don’t have circular needles and I can’t afford them, so I really need it to be knit flat. I prefer stockinette stitch, but perhaps I can glean the conceps from a simple pattern!

Have you looked through here yet? Maybe you can get some ideas there?