Put a dozen or so baby potatoes in a pot of water with 2 tsp kosher salt. Bring to a boil over high heat, reduce to a simmer, and cook until completely tender and can be easily pierced with a skewer (about 30–35 minutes).
Fold another dishtowel into quarters, and use it to gently press down on each potato with the palm of your hand to flatten it to a thickness of about 1/2 inch. Try not to break them, but don't worry if they do.
Cover a large rimmed baking sheet with aluminum foil and then parchment on top of that (Why? I don't know. I'm just following directions from Fine Cooking.) Transfer flattened potatoes carefully to prepared baking sheet and let cool completely at room temperature. (If desired, then cover loosely with plastic wrap and refrigerate for up to 8 hours.)
Heat oven to 450° (or 400° convection). Sprinkle the potatoes with 3/4 tsp kosher salt and pour 1/2 cup extra virgin olive oil over them. Lift the potatoes gently to make sure some of the oil goes underneath them and they are well coated on both sides.
Roast the potatoes until they're crispy and deep brown around the edges, turning after about 15 minutes, for about 30 minutes total for convection (or closer to 40 minutes if roasting conventionally).