2 garlic cloves, minced
1/4 cup chopped fresh basil leaves
1 cup kalamata olives, pitted and patted dry
1/4 cup extra-virgin olive oil
1/4 cup freshly grated parmesan cheese
12 small red or Yukon Gold potatoes (2 to 3 in. diameter), well-scrubbed
2 tablespoons minced flat-leaf parsley
Make pesto: Purée garlic and basil in a food processor. Add olives and oil and pulse to a smooth, thick paste. Turn into a bowl and stir in cheese.
Put potatoes in a large pot on the stove with generously salted water to cover. Bring almost to a boil and cook until easily pierced with a knife, 15 to 20 minutes. Drain. When cool enough to handle, press each between your hands until about 3/4 in. thick but still in one piece.
Spread each potato with 1 heaping tablespoon pesto and press to compact it. Heat a cast-iron skillet, then add potatoes. Pan-roast until crisp underneath, 5 minutes. Turn pesto side down and let roast and crisp up. Put on a platter, pesto side up, and sprinkle with parsley.