Slide the baking sheet into the preheated oven and bake for 25–35 minutes, or until the potatoes are deeply golden and the edges are very crisp. Rotate the pan halfway through baking so they brown evenly. If you like them extra crispy, leave them in a few minutes longer and watch closely toward the end.
Remove the pan from the oven and immediately sprinkle the hot potatoes with the chopped parsley or chives so the herbs cling to the buttery tops. Taste one and add a pinch more salt if needed.
Serve the smashed potatoes right on the foil-lined baking sheet or transfer them carefully to a warm platter, spooning any melted butter and herbs from the pan over the top. Enjoy while they’re still sizzling and crisp.
If you prefer, you can swap baby red potatoes for the yellow ones; they hold their shape nicely and get just as crisp. For even more texture, chill the boiled potatoes in the refrigerator for an hour before smashing and baking—this dries them slightly and can make the edges extra crunchy. You can also play with the size: very tiny potatoes can be left almost whole and lightly pressed, while larger ones should be smashed a bit thinner so they crisp up before the centers dry out. If you like a deeper buttery flavor, dot a few extra small pieces of Irish butter on top of the potatoes in the last 5 minutes of baking so they melt and glisten without burning. For make-ahead prep, boil the potatoes earlier in the day, keep them covered in the fridge, then smash, butter, and bake right before serving. Leftovers reheat well on a hot skillet or in a toaster oven, and they make a fine base for a quick breakfast hash with a fried egg on top (using whatever extra herbs you have on hand).
