Add penne pasta to the boiling water and cook according to package directions until al dente.
Drain the pasta in a colander and set aside.
Heat olive oil in a large skillet over medium-high heat.
Add onion to the skillet and sauté until soft, about 4 minutes.
Add garlic to the skillet and cook for 30 seconds.
Add ground beef to the skillet and break it apart with a wooden spoon.
Cook the beef until browned, about 6 to 8 minutes, then drain excess fat if needed.
Stir in crushed tomatoes, diced tomatoes, and tomato paste.
Add oregano, basil, red pepper flakes, salt, and black pepper, then mix well.
Lower heat to medium-low and simmer uncovered for 25 to 30 minutes, stirring occasionally, until the sauce thickens.
If using milk, stir it in during the last 5 minutes of cooking for a creamy texture.
Add the cooked penne to the ragu and toss until evenly coated.
Top with fresh basil leaves and grated Parmesan cheese.
Notes
Tips and Tricks
Drain the Fat - After browning the ground beef, check for excess fat in the skillet. Draining it keeps the sauce from becoming greasy and helps the flavors stay balanced.Stir Occasionally - While the sauce simmers, stir it every few minutes to prevent sticking and ensure even cooking. This also helps the sauce thicken properly.Adjust Consistency - If the sauce gets too thick, add a splash of pasta water or beef broth. If it's too thin, let it simmer a few extra minutes uncovered.Taste as You Go - Before serving, taste the ragu and adjust the salt, pepper, or herbs as needed. Everyone's preference is different, so make it your own.Save Pasta Water - Reserve about half a cup of pasta water before draining. You can use it to loosen the sauce or help it coat the pasta better.Use Fresh Garlic - Fresh garlic adds more flavor than jarred or pre-minced versions. Mince it finely so it distributes evenly throughout the sauce.
Storing and Reheating
Refrigerate - Store leftovers in an airtight container in the refrigerator for up to 4 days.Freeze - Place cooled ragu in a freezer-safe container or bag for up to 3 months. Thaw in the refrigerator overnight before reheating.Reheat on Stovetop - Place a serving in a saucepan with 1 to 2 tablespoons water. Warm over low heat, stirring until heated through.Reheat in Microwave - Transfer a portion to a microwave-safe dish, cover loosely, and heat in 1-minute intervals, stirring between each, until hot.