1. In a large nonstick skillet or saucepan, heat walnuts over medium heat until toasted, 3 to 5 minutes. Transfer to a bowl and set aside.
2. Add olive oil, water, and cauliflower to the pan and bring to a boil over medium-high heat. Cover pan and cook, shaking the pan occasionally, until cauliflower is just barely tender, about 5 minutes.
3. Remove lid and continue to cook, stirring occasionally, until liquid evaporates and cauliflower begins to sizzle in the oil, about 2 minutes. Add garlic and continue to cook, stirring constantly, until cauliflower is tender, about 2 minutes longer. Add lemon juice, walnut oil (if using), salt, pepper, parsley, reserved walnuts, and Parmesan and toss to distribute. Transfer to a platter and serve immediately.
Source: Fresh Magazine September, October 2010