Preheat the oven to 425°F and position a rack in the center. In a large bowl, combine the oil, chili powder, garlic powder, paprika, oregano, cumin, and 1 1/2 teaspoons of salt, whisking until well blended. Add the cauliflower florets to the bowl and toss until they are evenly coated with the mixture. Place the cauliflower florets cut-side down on a baking sheet lined with foil.
Roast the cauliflower in the oven for 25 to 30 minutes, until it's tender in the center and a deep brown on the bottom. Allow the cauliflower to cool for about 5 minutes on the baking sheet.
While the cauliflower is roasting, mix the sour cream, 1 tablespoon of lime juice, and 1/2 teaspoon of salt in a small bowl. Cover and refrigerate the mixture until you're ready to use it.
In another bowl, combine the sliced cabbages, thinly sliced onion, 1/4 cup of cilantro, the remaining 2 tablespoons of lime juice, and 1/2 teaspoon of salt. Mix everything together and let it sit at room temperature.
To assemble the tacos, take a tortilla and fill it with some of the cabbage slaw. Add several pieces of the roasted cauliflower on top, drizzle with the sour cream mixture, and finish with additional cilantro. Serve the tacos with lime wedges on the side.
Notes
This recipe does not specify prep and cook times. Enjoy these delicious tacos with lime for extra flavor.