Step 1

Finely chop 1 medium yellow onion and mince 3 garlic cloves. Heat 1 tablespoon olive oil in a large high-sided skillet over medium-high heat until shimmering. Add the onion, garlic, 1 pound lean ground beef, 1 teaspoon of the kosher salt, 1/2 teaspoon dried oregano, 1/4 teaspoon black pepper, and 1/4 teaspoon red pepper flakes, if using. Cook, breaking the beef up into small pieces with a wooden spoon, until the beef is cooked through, 5 to 7 minutes.

Step 2

Carefully pour in 1 (28-ounce) can crushed tomatoes and season with the remaining 1/2 teaspoon kosher salt. Bring to a boil. Reduce the heat to medium-low and gently simmer uncovered until the sauce is slightly thickened, about 20 minutes.

Step 3

Meanwhile, bring a large pot of salted water to a boil. Add 1 pound dried spaghetti and cook for 1 minute less than the package instructions for al dente, about 9 minutes. Reserve 1 cup of the pasta cooking water and drain the spaghetti.

Step 4

Return the pasta to the pot. Add the sauce, reserved pasta cooking water, and 2 teaspoons balsamic vinegar, and toss to combine. Bring to a simmer over medium heat, tossing continuously, until the sauce coats the pasta and everything is evenly combined, 1 to 2 minutes. Serve in bowls topped with lots of grated Parmesan cheese.