The distinctive red hue of this fantastic vegetarian taco recipe from Michael Natkin's blog Herbivoracious comes solely from achiote paste—a vibrant mixture of red achiote seeds, Mexican oregano, black pepper, cumin, and cloves (among other things), all ground up into a smooth paste. This specialty of the Yucatan region is aromatic and pungent, and (on a completely different note) has the ability to permanently stain anything it comes into contact with.
But it's worth the risk for such a filling and compelling meal as this one.
Considering the achiote paste is so flavorful, everything else here is easy. Just cut the butternut squash into half-inch slabs, rub with the paste, and grill until tender. The pieces took a little longer to finish cooking than I originally imagined, but just reduce the heat to medium-low if they outside starts to look a little too black.
If things get desperate, Natkin also notes that you can microwave the squash to get it 100 percent done. Though I was skeptical, this does work well.
As for the rest of the ingredients, the smoky poblanos add a subtle spice while the caramelized red onions get sweet and rich. The crema and cheese might seem unnecessary, but the two really help to pull all the ingredients together.