1 pound new (small) potatoes
1/2 teaspoon salt
2 tablespoons fresh lemon juice
5 tablespoons extra-virgin olive oil
1/4 teaspoon ground black pepper
1 pound cauliflower, cut or broken into small florets (no bigger than 1 1/2 inches)
1/2 cup chopped pitted olives (preferably a mix of black and green)
1/3 cup thinly sliced red onion (one quarter of a small onion)
1/4 cup chopped pepperoncini or other pickled peppers (about 4)
1 teaspoon fresh thyme leaves
1/2 teaspoon crushed red pepper flakes
3 ounces feta cheese
1/2 cup lightly packed arugula leaves, chopped
Preheat the oven to 375 degrees.
Put the potatoes in a large pot of cold, salted water, and bring to a boil over high heat. Reduce the heat until it's gently bubbling (medium-low), and cook until the potatoes are tender, 20 to 25 minutes. Drain and return them to the pot.
Use a fork to crush and smash the potatoes, creating lots of crevices. Add the lemon juice, 1 tablespoon of the oil, 1/4 teaspoon of the salt and the pepper, and toss gently. Let cool.
Toss the cauliflower on a rimmed baking sheet with another 1 tablespoon of the oil and 1/4 teaspoon of the salt. Roast until tender and browned around the edges, 20 to 30 minutes.
Add the just-roasted cauliflower to the smashed potatoes. Add the olives, red onion, pickled peppers, thyme and crushed red pepper flakes, and toss gently to incorporate.
Crumble the feta into the bowl of a mini food processor or blender; pulse until creamy. With the motor running, drizzle in the remaining 3 tablespoons of oil until well incorporated.
Add the whipped feta to the salad and fold gently. Add the arugula and fold again (unless you plan to serve the salad later, if so reserve the arugula and add at the last minute). Taste, and add more salt, pepper and lemon juice, as needed.
Serve slightly warm or at room temperature, with lemon wedges on the side.