Build the base: Heat olive oil and butter in a large Dutch oven over medium heat.
Add onion, carrot, and celery. Cook until soft and fragrant, about 7–8 minutes, stirring often to prevent browning. Add garlic and cook 1 minute more.
Brown the meat: Add ground beef and pork.
Season with salt, pepper, and red pepper flakes if using. Cook, breaking it up with a spoon, until browned and no longer pink, about 8–10 minutes. Spoon off excess fat if needed, leaving a little for flavor.
Tomato paste and deglaze: Stir in tomato paste and cook for 2 minutes to caramelize slightly.
Pour in the red wine and scrape up any browned bits from the bottom. Let it simmer until the wine reduces by half, 2–3 minutes.
Simmer the sauce: Add crushed tomatoes, milk, bay leaf, and oregano. Bring to a gentle simmer, then lower the heat.
Cook uncovered for 30–45 minutes, stirring occasionally, until thick and glossy. Taste and adjust seasoning.
Cook the pasta: While the sauce simmers, bring a large pot of salted water to a boil. Cook penne until al dente according to package directions.
Reserve 1/2 cup of pasta water, then drain.
Combine: Remove the bay leaf. Add the penne to the sauce, tossing to coat. If the sauce seems too thick, add a splash of the reserved pasta water to loosen and help it cling.
Finish and serve: Top with freshly grated Parmesan and chopped basil or parsley.
Serve hot, with extra cheese at the table.