Cook the potatoes in boiling salted water until tender, about 30 minutes. Drain.

While they are cooking, make the sauce: In a large sauté pan, melt the butter over medium-high heat. When it is foaming, add the onion and cook until lightly caramelized, about 8 minutes. Add the tomatoes, season with salt and pepper, and cook for 7 minutes, or until the tomatoes start to break down. Add the cream, bring to a simmer, and sprinkle in the cheese. Allow it to melt, and cook for another 3 minutes. Pour half the sauce into a small pot and keep warm.

In a bowl, toss the romaine with the remaining sauce until the lettuce is warm. Arrange on a large platter. Place the potato wedges on top, drizzle them with extra virgin olive oil, and season with salt and pepper. Spoon the remaining sauce over the potatoes. Garnish with chopped fresh herbs, if you like.