Preheat your oven to 425°F (220°C). In a large pot, bring salted water to a boil, and add your baby potatoes. Cook for 7-8 minutes until fork-tender. Drain and cool slightly.

On a lined baking sheet, place each cooled potato and use a glass bottom or potato masher to smash them to about 1/4 inch thick. Brush each with olive oil and season with salt and pepper.

Roast the smashed potatoes for 45-60 minutes, flipping halfway, until golden and crispy. Monitor closely towards the end.

While roasting, combine Greek yogurt, Kewpie mayo, Dijon mustard, lemon juice, and minced garlic in a bowl. Stir until smooth and adjust seasoning.

Once potatoes are slightly cooled, mix them with the dressing and toss gently to coat. Reserve some crispy bits for topping.

Garnish with reserved crispy potato bits and chopped scallions. Serve warm or at room temperature.