This took me 45 minutes with kids crawling all over me, so probably less time for the focused and un-disctracted (unless you have kids that like to help you sew too, then 45 minutes at least). I used my square top tutorial (my favorite as usual) because it is easy and I love the fit.
1/4 yard of lace (or whatever material you want)
button up shirt (make sure it will be long enough)
1. Cut off from just under the armpit curving up a few inches to the center, then back down to the under the armpit.
2. Cut the back side to be a little shorter then the front.
3. Trace with a top - you like the fit of (I like a loose fitting square top). Cut out.
4. Sew the side seams and the shoulders of the top lace half. Try on and make sure it is how you like it. I ended up cutting the front half of the lace 2 inches off by tapering it from the armpit to the center 2"-3" and back to the armpit.
5. Turn the button up lower half inside out and turn the lace upper half right side out, slide the lace top into the bottom, and match up the openings. Make sure the openings side seams match up well. If not, then take in the bottom half (I had to take it in a few inches). Sew the openings together. Try it on and make adjustments if needed.
6. Line up the side seams and cut out a neckline.
7. Hem the neckline and the sleeves.