Place the potatoes in a large pot of well-salted water. Boil until fork-tender but not falling apart. Drain thoroughly and allow the potatoes to steam dry for a few minutes. This step removes excess moisture, which helps them crisp later.

Transfer the potatoes to a lined baking sheet. Use the bottom of a glass or a potato masher to gently press each potato until flattened but still intact.

Drizzle the smashed potatoes generously with olive oil and season with salt, pepper, and garlic. Roast in a hot oven until golden brown and crisp around the edges, flipping once to ensure even browning.

Whisk together mayonnaise or Greek yogurt, mustard, lemon juice or vinegar, and seasoning. Add a small amount of honey or maple syrup if you prefer a slightly rounded flavor.

Allow the potatoes to cool slightly, then gently toss them with the dressing, herbs, and any optional add-ins. Taste and adjust seasoning before serving.