I may have to read Harry Potter after making this cute baby costume!
The scarf was super easy. I cut rectangles and sewed them together with a zig zag stitch.
I put red thread on top, yellow on bottom, and stitched them together.
Then I used my Silhouette to cut out a tie in red, and one in yellow. I cut the stripes and ironed them on to the red tie, and then onto the onesie.
The vest was an adventure... It took me a few tries, but I based it off this tutorial.
It kinda ended up small, so I added a back and made it a real vest.
To make the cape I used a small black t-shirt and followed this tutorial: http://www.piecesbypolly.com/2013/11/super-fast-and-easy-diy-harry-potter.html