Preheat the oven to 400°F (200°C).

Chop the cauliflower into bite-sized florets and spread them on a baking sheet. Drizzle with lemon juice, olive oil, salt, and pepper, and toss to coat.

Roast the cauliflower for about 30 minutes, stirring halfway through for even browning.

Steam the broccoli in a steamer basket over simmering water for 4-5 minutes until bright green.

In a mixing bowl, whisk together tahini, lemon juice, salt, garlic powder, and water to achieve a smooth dressing.

To assemble, lay a bed of spinach in serving bowls. Top with roasted cauliflower, steamed broccoli, avocado slices, and seeds. Drizzle with tahini dressing.

Adjust seasoning with hot sauce, lemon juice, or more salt as desired and serve immediately.