According to Iroquois legend, corn, beans, and squash are three inseparable sisters who only grow and thrive together. This tradition of inter-planting corn, beans and squash in the same mounds, widespread among Native American farming societies, is a sophisticated, sustainable system that provided long-term soil fertility and a healthy diet to generations.
Preheat oven to 375°.
Halve squash lengthwise and remove seeds. Bake cut side down on a baking sheet until slightly tender but still firm, about 20 minutes. Remove from the oven and raise temperature to 425°.
When squash is cool enough to handle, remove the skin with a knife and chop the squash into 1 inch cubes. Toss cubed squash with olive oil, chili powder, salt and pepper. Return to the oven and roast for 15-20 minutes, until it begins to brown and caramelize.
If using canned beans, rinse and drain. If desired, warm them in a pan with olive oil, chopped garlic, and cumin. If using dried beans, follow the recipe for Slow Cooker Black Beans. Keep the beans warm. If using soft corn tortillas, wrap in aluminum foil and heat in the oven for 5-10 minutes.
Assemble tacos with beans, squash, and desired garnishes.