Makes about 2 quarts
In a large saucepan or Dutch oven, heat olive oil over medium heat and, when hot, add pancetta and cook until golden brown and slightly crispy, about 3 minutes. Increase heat to medium-high; add onion and cook until softened and beginning to caramelize, about 6 minutes. Add garlic and cook until fragrant, 1 to 2 minutes. Add tomatoes with juices and stir to combine. Add oregano, salt, and crushed red pepper, reduce heat to a simmer, and cook for 30 to 40 minutes or until sauce is slightly thickened. Add basil, stir to combine, and let sit for 5 minutes before serving.