They are so easy it’s embarrassing so I thought I would just write out what I did with some of my super fantastic hand drawn pictures instead of making you wait until I feel like making another pair, which might be until the weather gets a lot warmer. A little lame but hey… here goes!
They are basically a modified pillowcase dress made out of knit. Easy peasy. The two I made were about a girls size 10 so my directions are based on that. Tweak away for bigger or smaller sizes. I made mine with my serger and my machine but I have made them with just my machine before. Use a ball point needle and you’ll be fine since they don’t need to stretch.
First I cut out 2 pieces of fabric for the back and front. I used the width of my fabric for the width and measured from the chest to the knee for the length. So each of my pieces were about 55” wide x 30” tall. I know that’s a ton of fabric width wise but that’s what makes it look good, especially for knit. For adult sizes I would keep the width the same just adjust the length.
Grab one piece for your front and measure from the top down, on the fold, 1 1/2”. Cut from that mark up to the outside edge corner like so. You only need to do this to the front piece. The back should be straight across the top.
Now you mark the armscye by measuring about 2 1/2” from the outside edge toward the center and 5” down from the top. You want to round the bottom corner so it’s more of a “J” shape than a rectangle and cut through all thicknesses for the front and back piece. 
*If you want to make ruffling easier you can sew gathered strips of 4” wide fabric to the bottom of the front and back pieces here and sew them together when you sew the sides up. That’s what I did but forgot and had to edit that in here.*
Now put the front piece on top of the back piece with right sides together and sew down the straight sides.
Fold the armscye edges under toward the inside 1/4” and then another 1/4” and sew along the outside edge.
Fold the top neck edges down 1/4” and then another 1” and sew close to the edge for the front and back. Don’t sew the sides of that seam shut, this is the casing for the tie.
For the neck tie cut a strip of fabric the width of your fabric (55”-60” long) by 4” wide. Fold in half right sides together and sew along the open edges rounding the corners as you go. Leave a space open in the middle for turning. Turn right side out and sew the opening shut.
For the ruffle cut strips of fabric 4” wide and sew them together right sides together. The amount of strips you need will depend on how gathered you want it and how big you are making your jammies.
Sew the ruffle on the bottom right sides together then topstitch to keep it laying nice and flat. Thread the tie through the casing in the neck and tie in a big fat adorable bow.
I’ll try to answer questions in the comments for all to see. Hope your Monday just got a bit better!
