Preheat your oven to 400°F and line a small baking sheet with parchment paper.
Toss the broccoli florets with olive oil, salt, and pepper, then roast for 15-20 minutes until the edges are slightly charred.
While the broccoli roasts, steam the cauliflower florets in a steamer basket over boiling water until they are very fork-tender, approximately 10 minutes.
Transfer the steamed cauliflower to a food processor or bowl, adding the ghee, minced garlic, and a pinch of salt, then blend or mash until smooth and creamy.
Pat the salmon fillet completely dry with a paper towel and season both sides with salt and pepper.
Heat a high-quality non-stick skillet over medium-high heat and place the salmon skin-side down, searing for 4-5 minutes without moving it to ensure the skin becomes golden and crisp.
Flip the salmon carefully and cook for an additional 2-3 minutes until the fish is opaque and cooked to your desired level of doneness.
Plate the salmon alongside the roasted broccoli and garlic cauliflower mash, finishing the dish with a fresh squeeze of lemon juice.