In a sauté pan over medium-low heat, add 1 teaspoon oil, capers and sunflower seeds. Cook for 3 to 4 minutes, shaking the pan occasionally, or until capers and sunflower seeds are lightly toasted. Transfer to a bowl, and set aside.
Return the pan to the heat. Add 2 tablespoons oil and shallots. Sauté 2 to 3 minutes, until shallots are translucent. Add cauliflower, and toss. Cook 5 to 7 minutes, shaking the pan occasionally, until cauliflower is slightly browned. Add 1 to 2 tablespoons water to the pan, and cover. Let steam for 4 to 5 minutes, or until cauliflower is softened. Add cayenne pepper, and toss to coat. Add 3/4 of the caper-sunflower seed mixture, and shredded Gruyére to the pan. Gently stir until cheese is melted.
To serve, transfer cauliflower mixture to serving bowl, and top with remaining caper-sunflower seed mixture, and fresh or dried parsley. Serve with side of sweet mustard, if desired.