Preheat your oven to 400°F and line a baking sheet with parchment paper.
Toss the broccoli florets with half of the avocado oil, salt, and pepper, then roast for 15-20 minutes until the edges are charred.
Steam the cauliflower florets in a steamer basket over boiling water for 10-12 minutes until they are very tender.
Transfer the steamed cauliflower to a blender or food processor and add the ghee, minced garlic, chives, and lemon juice, blending until smooth and creamy.
Season the salmon fillet with a pinch of salt and pepper.
Heat the remaining avocado oil in a non-stick skillet over medium-high heat.
Place the salmon skin-side down in the pan and sear for 4-5 minutes, then flip and cook for another 3-4 minutes until the fish is golden and flakes easily with a fork.
Spread the herb-cauliflower mash onto a plate, top with the seared salmon, and serve alongside the roasted broccoli.