01 - Set the oven to 425°F. Prepare a baking sheet lined with parchment paper or a silicone mat.
02 - Place the potatoes in a large pot, cover with cold water, and add 1 tablespoon kosher salt. Bring to a boil and simmer for 15 to 20 minutes, until the potatoes are just fork-tender.
03 - Drain the potatoes thoroughly and let them steam-dry for 5 minutes for optimal crispiness.
04 - Arrange the cooked potatoes on the prepared baking sheet. Using the bottom of a sturdy glass, gently press each potato to a thickness of about 1/2 inch. Drizzle with olive oil and season with salt and pepper.
05 - Roast the potatoes in the oven for 25 to 30 minutes, flipping halfway, until the edges are golden and crispy.
06 - While the potatoes roast, whisk together mayonnaise, Greek yogurt or sour cream, Dijon mustard, lemon juice, honey, minced garlic, and a pinch of salt and black pepper in a medium bowl until smooth. Adjust seasoning to preference.
07 - In a large mixing bowl, combine chopped red onion, celery, fresh herbs, radishes, and capers if using.
08 - Allow the roasted potatoes to cool for 5 minutes. Add the potatoes to the bowl with salad mix-ins.
09 - Drizzle with the creamy dressing and gently toss to coat. Serve immediately for the best crisp texture or at room temperature.