Heat a large heavy-bottomed pot or Dutch oven over medium heat. Add olive oil and butter. When butter melts, add diced onion, carrot and celery. Cook, stirring occasionally, until vegetables are soft and translucent, about 7–9 minutes. Add minced garlic and chopped pancetta; cook 2–3 minutes until fragrant and pancetta begins to render fat.

Brown the meats

Increase heat to medium-high. Add ground beef and ground pork in a single layer. Break up with a spoon and cook undisturbed 3–4 minutes to get some browning, then continue stirring and cooking until meat is no longer pink, about 6–8 minutes total. Season with 1 tsp of salt and 1/2 tsp of black pepper while cooking.

Add milk

Reduce heat to medium. Pour in the milk and add the freshly grated nutmeg. Simmer gently, stirring occasionally, until milk is mostly absorbed, about 8–10 minutes. This step softens acidity and adds richness.

Deglaze with wine

Add the white wine and scrape up any browned bits from the pot. Let wine reduce until mostly evaporated, about 4–6 minutes.

Build the sauce

Stir in the tomato paste and cook 2 minutes to caramelize. Add crushed tomatoes, stock, bay leaf and thyme. Bring to a gentle simmer. Taste and add remaining 1/2 tsp salt, 1/4 tsp black pepper and sugar if desired to balance acidity.

Long simmer

Reduce heat to low so sauce barely bubbles. Partially cover and simmer gently, stirring occasionally, until thickened and flavors have deepened, 1.5–2 hours. If sauce thickens too much, add small splashes of stock or water to keep a loose but hearty consistency. Remove bay leaf and adjust seasoning at the end.

Pasta & Finishes

Cook rigatoni

About 15–20 minutes before sauce is done, bring a large pot of water to a rolling boil. Add 1 tbsp salt. Cook rigatoni until just shy of al dente according to package directions (usually 10–12 minutes), reserving 1–1.5 cups of pasta cooking water before draining.

Combine pasta and sauce

Add drained rigatoni to the pot with Bolognese (or transfer sauce into the pasta pot). Toss gently over low heat, adding 1/3 cup of reserved pasta water at a time as needed to help sauce cling to the pasta and achieve desired consistency. Cook together for 1–2 minutes so pasta finishes cooking in the sauce and absorbs flavor.

Finish and serve

Remove from heat. Stir in 1/2 cup of the grated Parmesan and the optional 1 tsp olive oil to add silkiness. Taste and correct seasoning with salt and pepper. Divide rigatoni Bolognese among bowls, sprinkle remaining Parmesan on top and garnish with torn basil if using. Serve immediately.