Heat a heavy-bottomed Dutch oven over medium-high heat. Once hot, add the bone-in beef shanks, searing them for about 8–10 minutes until a rich, golden crust forms on all sides. Use tongs to turn them for even browning. Once nicely caramelized, remove the shanks and set them aside on a plate while you prepare the soffritto.

In the same pot, lower the heat to medium and add chopped carrots, celery, and onions. Sauté these aromatics for 15–20 minutes, stirring occasionally, until they become soft and caramelized. After the soffritto is beautifully golden, stir in minced garlic and tomato paste, cooking for an additional 2 minutes until fragrant.

Pour in a generous splash of red wine, scraping the bottom of the pot to lift any flavorful browned bits. Allow the wine to simmer for about 5 minutes, reducing slightly. Next, add homemade beef stock and smooth tomato passata, along with your tied fresh herbs. Return the browned beef shanks back to the pot.

Increase the heat until the pot reaches a gentle boil. Once boiling, reduce the heat to low, cover the pot, and let it simmer for approximately 3 hours, basting the shanks occasionally.

Check for tenderness after 3 hours; the meat should be fork-tender and fall off the bone. Allow the osso buco to rest for about 10–15 minutes before serving.