Trim tough tops and root ends of the leeks. Halve them lengthwise and thinly slice. Fill sink or large bowl with water and wash leeks, separating layers and swishing them around in water. Dry in a salad spinner or on kitchen towel and reserve.
Bring a large pot of water to a boil for the pasta.
Heat a deep skillet over medium-high heat with EVOO, 2 turns of the pan. Add bacon and crisp. Add reserved leeks and garlic, cook 2-3 minutes to soften. Season liberally with black pepper.
Add tomatoes and purée to pan and mash up tomatoes. Bring up to a simmer and let thicken over low heat while you cook pasta. Stir in parsley.