Fairly straight forward.
I mount the blank on a screw chuck, true it up.
glue some scrap on the face to form a spigot, reverse so I can put it in my gripper jaws of my Ax. precision chuck.
Draw 3 parallel lines for the base, the middle, and the slope where the holes are not fogetting the lip.
I've made an indexing plate (cos my lathe don't have one).
Mark off 12 equidistant points. Drill a hole 10mm up from the top centre line at each marked point, the depth is not really important so long as it goes as far as the lip.
Rough turn the base, it will be finished when it's reverse chucked.
Turn the top slope, and lip, then hollow out. finish the inside, and top. Then reverse chuck with the jaws inside the lip. (I wind a few rounds of electrical insulating tape around the jaws so that it doesn't mark the lip. (I use that tape because it stretches) Then turn off the base spigot and finish.
I think that's it, it seems easier to do than write it.
Ha! Iv'e just reread it and forgot to say how I did the scallops.
I used a biscuit because it was the right shaped arc between the points below the holes.
bandsawed the waste then sanded the arc on my bobbin sander.
John. B