Drizzle cauliflower with olive oil and season with taco seasoning. Toss to coat evenly with seasonings and then spread out on a large baking sheet. Use 2 pans if needed so that the cauliflower is not overcrowded and can roast properly.
Roast for 30-40 minutes, until tender and browned, flipping once during the cooking process.
Make Avocado Lime Sauce
Place ripe avocado in a blender or mini food processor. Add in fresh lime juice, lime zest, and salt to food processor and blend until smooth and creamy, scraping down sides if needed. If you need to thin out your sauce, add in 1 tablespoon of cold water.
To serve Cauliflower Tacos, place roasted cauliflower onto tortilla or lettuce wrap. Drizzle with avocado sauce and top with pickled red onions, cilantro, and cheese if using.
Taco Seasoning: In place of homemade taco seasoning, use ¼ teaspoon each of salt, garlic powder, cumin, paprika, onion powder, and chili powder. Leftovers: Store leftover roasted cauliflower in the refrigerator for 4-5 days. Reheat by broiling for 2-3 minutes. Don't microwave the cauliflower or it will lose its texture.