Because some of you mentioned wanting to copy it (I'm honoured. If you do and blog about it, please let me know), I thought I would try and provide some extra instructions.
As you probably guessed, drafting this dress is not exactly rocket science. Or even proper hard-core pattern making. Anyone with some understanding of sewing and patterns should be able to make it. With the help of a tried-and-tested pattern for a fitted t-shirt with sleeves, that is.
I'm going to explain the steps using just a back pattern piece but the front is the same. If your pattern has bust darts, you can convert those into the seam between the front bodice and the lowest band of the yoke.
The pattern pieces as sketched (nothing is to scale, these are illustrations not actual patterns) don't have seam allowance. When doing alterations like this, it makes you job a lot easier to work like that. Just add them back on to the pattern pieces you end up with.
Before you begin, consider the fit of your pattern. Most real t-shirt patterns are rather rectangular but for this dress you want a fairly fitted waist, so you may have to take the side seams in a bit further at that point (to get a fit like mine, you also shouldn't have a lot of negative ease at the chest but that is a matter of preference). Of course, you can correct this while sewing, if you don't serge on the whole skirt without trying the dress on first.
An easy thing first: That dropped waist seam. Mine sits at 10 cm below the waistline (and I'm 1.68 which I think is still Burdastyle's standard height). It's basically a straight line but the ends near the side seams are curved a bit to form a 90 degree angle to those seam lines. Of course, you should make sure the side seams match up. This is how you avoid strange pointy bits at the side.
Than you have to start planning that yoke. Part of its charm, and all of its difficulty, is that the yoke extends just a bit past the shoulder.
Take your half sleeves and trace each onto the appropriate bodice piece. This is hard to draw well, but the top of the sleeve should meet the shoulder point on the bodice, the sleeve head can overlap a bit at the shoulder and there should be some open space left over where sleeve and bodice curve in. Compared to the shoulder, the sleeve will slope down a bit.
Now you can draw in the yoke pieces. This starts at the neckline. If you want a turtle neck, like my dress has, you need a fairly high neckline but it should still be wide enough to fit over your head. I think neckline on the bodice pattern was about 50 cm in total (the turtle neck piece itself is a band of fabric of 40 cm high and 42 wide, including seam allowance. In a firm knit like the pointe, that makes for a rather high neck which I can just pull over my head. I like it, but I have a long neck). Obviously, the front neckline should be clearly lower than the one at the back.
Draw concentric circles around the neckline. In my pattern, the top one is 4 cm wide, the other three are 5 cm. That worked better with the position I wanted for the bottom edge of the yoke (to get rid of the bust dart in my knit sloper).
The actual yoke pieces are shaped as I mentioned it my previous post: They are straight bands of fabric, as long as the measurement of their top edges on the pattern.
There's just one more thing to do to the bodice piece now: adjust the sleeve. A bit of a raglan sleeve effect looks better under a yoke like this, so you adjust the armscye accordingly. Cut off the little piece.
Cut off the half sleeves along the bottom of the yoke and stick them back together. The middle of the top will look a bit odd but you are working with a stretchy fabric. Just connect the sides in a straight line. And add on the raglan-bits. The pieces from the bodice won't fit easily on the sleeve but you use them more as a guide: They determine how much width you have to add to the top of the sleeve and then you just draw gentle curves to the underarm point. Make sure to check if the lengths of the 'armscyes' on bodices and sleeve match each other though.
And the skirt? That is just a rectangle. Mine uses a little less (because the material close to the selvedge was a bit weird at one side) than twice the width of the fabric, so its about 2.60 cm wide in total. The finished length of my skirt is about 50 cm and I made a deep hem.
I hope this will help anyone who wants to try and make this cozy dress for herself. As usual, if anything isn't clear, just ask and I'd love to see what you make from this.