While the potatoes will cook, prepare everything else so you can work efficiently. Finely chop the parsley, dill, and scallions, keeping them separate for now. Crush the garlic cloves with the side of your knife to release their oils. In a small bowl, whisk together the olive oil, champagne vinegar, crushed garlic, Dijon mustard, salt, pepper, and red pepper flakes until the mixture is emulsified and smooth. This dressing can sit while the potatoes cook—in fact, I prefer to make it ahead so the flavors have time to meld together.

Place the small Yukon Gold potatoes in a large pot of cold salted water. Bring to a boil over high heat, then reduce to a simmer and cook for 20-30 minutes until the potatoes are fork-tender but still hold their shape—you want them cooked through but not falling apart. Drain them well and let them cool for about 10 minutes. While they're still warm, cut them into bite-sized chunks (about 1-inch pieces). The warm potatoes will absorb the dressing better than cold ones, which is key to building flavor in this salad.

Transfer the warm potato chunks to a large bowl. Pour the dressing from Step 1 over the potatoes and toss gently but thoroughly to coat every piece. Add the chopped parsley, dill, and scallions, folding them in carefully to distribute the herbs evenly. Taste and adjust the seasoning if needed—I like to add just a touch more salt at this stage because the potatoes absorb flavors beautifully. Serve warm or chilled according to your preference, knowing that the flavors will continue to develop as it sits.