Preheat oven to 400 degrees F. Toss the florets with 3 tablespoons olive oil, salt & pepper. Spread the florets onto a foil lined baking sheets and roast, tossing occasionally, until tender and golden brown, about 25 to 30 minutes. While the cauliflower is roasting, place the remaining olive oil, parsley, garlic, anchovy, capers, salt, pepper, and lemon juice in a blender or food processor. Pulse until the mixture is finely chopped but still has texture. When the cauliflower has finished roasting, toss with the dressing. Spoon the cauliflower into a serving bowl, top with lemon zest and serve.