In a large sauté pan over medium heat, cook the bacon until crispy. Remove the bacon with a slotted spoon and drain on a paper towel-lined plate. Carefully remove and discard the bacon fat, leaving only about 2 tablespoons in the pan.
Add the extra virgin olive oil, onions, pepperoncini, and red chili flakes to the pan. Cook over medium-low heat, stirring occasionally, until the onions are translucent, about 7 to 8 minutes.
Stir in the garlic and cook for 2 minutes until fragrant. Add the tomato paste and sauté until it deepens in color, about 3 to 5 minutes.
Stir in the crushed tomatoes, cooked bacon, salt, black pepper, and sugar. Bring to a boil, then lower the heat and let simmer for 30 minutes, stirring occasionally. Add the basil, taste for seasoning (it will be spicy!), and keep warm over very low heat.
Meanwhile, bring a large pot of water to a full boil. Add the kosher salt, then cook the pasta according to the package instructions.
Two minutes before the pasta is al dente, use a spider strainer or tongs to transfer it directly into the sauce. Add ½ to 1 cup of reserved pasta water and simmer for 2 to 3 minutes until the pasta is perfectly al dente and well coated in the sauce.
Spoon the pasta into shallow bowls and top with extra basil and freshly grated Parmesan cheese. Serve hot and enjoy!