1. 1. Preheat the oven to 400°F (200°C).

2. 2. Season the salmon fillets with salt, pepper, and a squeeze of lemon juice.

3. 3. Place the seasoned salmon fillets on a baking sheet lined with parchment paper.

4. 4. In a bowl, mix cauliflower rice with diced carrots, zucchini, celery, fresh onion, button mushrooms, and leeks.

5. 5. Add feta cheese crumbles to the vegetable mixture and mix well.

6. 6. Stuff the vegetable mixture into the cavity of each salmon fillet.

7. 7. Bake in the preheated oven for 20-25 minutes, or until the salmon is cooked through and the vegetables are tender.

8. 8. Serve hot and enjoy!