OmNomNom!

My son and I baked gluten-free hamentaschen for Purim this weekend, and then were not a 100% success. This is a baked good that has bested me before; the last time I made them, I used too much xanthan gum (which helps the dough stick together, be springy, and be strong enough to roll and shape), and the pinched-together edges wouldn't stick and ended up unfolding in the oven. This time, I worked from this recipe, which I'll reproduce under a cut:

( Yummy Gluten-Free Hamentaschen, recipe by Rella Kaplowitz )

This time, the dough didn't give me any of the same problems: it rolled out nicely, stuck together but didn't bounce back too much, and pinched into hamentaschen shapes very easily. However, in the oven the cookies melted down and turned into vaguely triangular flat puddles of cookie. They taste fantastic, but they don't look like hamentaschen.

( photographic evidence )

So, what did I do wrong?

I've got a couple of possibilities:

1) I used butter instead of margarine. But they have nearly identical melting points, so that shouldn't have made a difference.

2) Insufficient dough chilling. The recipe called for the dough to be chilled for one hour before rolling; I only chilled it half an hour, because I was working with the constraints of preschooler-bedtime creeping up on me. The dough rolled out fine, which is usually why you chill GF doughs--to get them solid enough to work with. However, it seems likely that the butter needed to be more solid going into the oven to allow them to keep their shape. If this seems like the case, then I think they'd need to be chilled after forming them, because working with the dough to shape them, not to mention keeping them out on the counter while you make the rest, would let them get warm.

3) Oven over-crowding. Both my top and bottom rack were full of cookies, and both of the sheets were crowded. That could have allowed the butter to melt more before the cookies set up, if they weren't cooking fast enough.

4) Something specific to GF baking. For the record, I don't think this is it--the recipe worked fine at every step up until they went into the oven, including rolling, which is always tricky. Plus, the first two are the only deviations from the recipe involved, and, given the way the hamentaschen look in her photo, they seem to have come together OK.

What's your guess on what went wrong with these cookies? I'd like to make a note for myself, so when I make them next year they can be equally delicious but slightly better looking, lol.