Preheat the oven to 425°F and line a large baking sheet with parchment paper.

Boil the baby potatoes for about 7 minutes until fork‑tender, then drain and pat dry.

Place the potatoes on the prepared sheet, smash each with the bottom of a glass, brush with olive oil, and season with salt and pepper.

Roast the smashed potatoes for 50–60 minutes, until golden and crispy. Reserve a few crisp bits for garnish.

While the potatoes roast, whisk together Greek yogurt, mayonnaise, Dijon, lemon juice, red wine vinegar, garlic, dill, parsley, salt, and pepper to make the dressing.

Stir in the cucumber and shallot, then cover and refrigerate the dressing until the potatoes are ready.

When the potatoes have cooled for 5 minutes, toss them gently with the chilled dressing until fully coated.

Garnish with the reserved crispy potato bits, extra dill, and a pinch of black pepper. Serve warm or at room temperature.