2 tablespoons extra virgin olive oil
1 small butternut squash
1 teaspoon salt
1/2 teaspoon ground cinnamon
1 teaspoon ground cumin
1/2 teaspoon freshly ground black pepper
1 1/2 cups refried black beans
8 soft corn tortillas
Pickled Shallots (see recipe), sliced
Cilantro sprigs, for serving
3 serrano chiles, seeds removed if desired, diced
Crema, crème fraiche, or sour cream, for serving
Cut the butternut squash in half crosswise at the narrowest point. Cut each half in half again lengthwise. Peel each section with a vegetable peeler or a flexible sharp knife. Use a teaspoon to scrape out the seeds and strings. Cut into 1/2-inch dice. Heat large nonstick skillet over high heat. Add olive oil. When it smokes, add squash cubes and toss well. Sprinkle salt, cinnamon, cumin, and black pepper. Sauté over high heat, tossing frequently, until browned outside and tender but not mushy inside, about 10 minutes.
Meanwhile, warm the refried beans gently over low heat.
To serve, heat tortillas quickly one by one in a very hot dry skillet, about 10 seconds per side. Assemble tacos by spooning black beans onto tortillas, topping with sautéed squash, Pickled Shallots, cilantro sprigs, diced serranos, and crema.