01 - Preheat oven to 425°F. Line a large baking sheet with parchment paper and set aside.
02 - In a large mixing bowl, toss the cauliflower florets with 2 tablespoons of olive oil, dried oregano, garlic powder, ground cumin, salt, and freshly ground black pepper until evenly coated.
03 - Spread the seasoned cauliflower in a single layer on the prepared baking sheet. Roast for 20 to 25 minutes, flipping halfway through, until the edges are golden brown and the florets are fork-tender.
04 - While the cauliflower roasts, halve the cherry tomatoes, dice the cucumber, thinly slice the red onion, and slice the Kalamata olives.
05 - In a separate bowl, gently toss the baby spinach with the remaining 1 tablespoon of olive oil and a light pinch of salt.
06 - Divide the dressed spinach among four serving bowls as the base. Arrange the roasted cauliflower, cherry tomatoes, cucumber, red onion, and olives over the greens in each bowl.
07 - Crumble feta cheese over each bowl, drizzle with tzatziki sauce, and garnish with fresh chopped dill. Serve immediately with lemon wedges on the side.