Complex sentence: Often mistaken for a survivalist, Gibbons actually advocated the use of nutritious but neglected plants, which he typically prepared not in the wild, but in a kitchen with abundant use of spices, butter and garnishes.
Split into simpler sentences: Often mistaken for a survivalist, Gibbons was simply an advocate of nutritious but neglected plants. He typically prepared these not in the wild, but in the kitchen with abundant use of spices, butter and garnishes.