Preheat your oven to 425°F (220°C). On a baking sheet, toss the cauliflower florets with 1 tablespoon of olive oil, salt, and pepper. Spread them out in a single layer and roast for about 20-25 minutes, or until the edges are golden brown and crispy.
In a large skillet over medium heat, add the remaining 0.5 tablespoon of olive oil. Once hot, add the ground beef. As it cooks, break it apart with a spatula. Once browned, drain any excess fat.
Stir in the garlic powder, onion powder, ground cumin, smoked paprika, chili powder, salt, and pepper. Cook for an additional 2-3 minutes until fragrant. Remove from heat.
In serving bowls, layer the roasted cauliflower as the base. Top with the seasoned ground beef. Then, add your desired toppings: shredded cheese, halved tomatoes, a dollop of sour cream, avocado, chopped red onion, and shredded iceberg lettuce.
Finish with a squeeze of lime juice over the top and serve immediately while everything is warm and fresh.