Preheat the oven to 375°F (190°C).
Prepare a baking dish by lightly greasing it with olive oil.
Place the salmon fillets in the dish skin-side down.
Drizzle olive oil and lemon juice over the salmon.
Sprinkle garlic powder, salt, and pepper over the fillets.
Slice the avocado in half, remove the pit and scoop out the flesh.
Spread the avocado evenly over the salmon fillets.
Crumble feta cheese over the avocado layer.
Bake in the preheated oven for 18-20 minutes.
Remove from the oven and let it rest for 5 minutes before serving.
Garnish with additional lemon juice if desired and serve.
