Knit in the round from the center out, using double-pointed needles.
Notes from designer’s page:
Here’s a pattern I developed which gives a simple stockinette six-pointed star--suitable for snowflakes for your Christmas tree or Stars of David for your Hanukkah bush. One knitter has reported attaching these to a length of I-cord to make bookmarks. In size 10 crochet cotton on US2s, this is more than 4 inches across.
I don’t know how far this pattern can be extended without running into some sort of trouble, but as it gets bigger the stockinette portions give some space for lace patterns, and crocheting around the edges can also add some snowflakey elements. This pattern can probably be worked as a 5-pointed star by casting on 10 instead of 12, but I haven’t tried this.
As to stiffening, I prefer starch over white glue for two reasons: starch can be washed out and redone if the object gets crumpled, and white glue isn’t all that white, it’s a tad yellowish.