Rinse the rainbow trout and pat it dry
Preheat the oven to 400°F
Season the fish inside and out with salt and pepper
Stuff the cavity with lemon slices, garlic, and fresh herbs if desired
Brush the outside with olive oil or melted butter
Place the trout on a lined baking sheet or in a lightly greased baking dish
Bake for 12 to 18 minutes, until the flesh flakes easily with a fork
Remove from the oven and let it rest for a few minutes
Serve with additional lemon wedges if desired