Snapper with juice

6 red snapper fillets , boneless and skinless 2 garlic cloves , crushed 3 ounces olive oil 1/3 lb onion , diced 1/3 lb celery , diced 1/3 lb mushroom ,[...]

4 teaspoons extra-virgin olive oil, divided 1/2 teaspoon kosher salt, divided 1/2 teaspoon freshly ground black pepper, divided 2 (6-ounce) snapper fillets 2[...]