Preparation

• Heat an 8- or 9-inch skillet over medium heat. Pour in the olive oil and add the whole garlic cloves. Cook the garlic until browned, about 8 minutes. Discard the cloves.
• Add the diced onion to the pan. Sauté in the oil until light brown, about 12 minutes. Remove the onions from the pan with a slotted spoon.
• Add half of the potato slices to the oil. Top them with an even layer of the onions, chopped garlic, tomatoes, salt, and pepper. Top with the remaining potato slices.Cook the potatoes until browned, about 15 minutes, and then turn the potatoes over, pressing down on them with a spatula. (You don’t have to turn all the potatoes at once; the potato cake will still keep its shape.) Continue cooking until the underside is brown and the potatoes are tender throughout, about another 15 minutes. Slide from the pan onto a serving platter and serve immediately.