For the Osso Buco:

Season the veal shanks with salt and pepper.
Dredge the shanks in flour and shake off any excess.
Heat the olive oil in a large Dutch oven or oven-safe pot over medium-high heat.
Brown the shanks on both sides, about 3-4 minutes per side.
Remove the shanks from the pot and set aside.
Add the onion, carrots, celery, and garlic to the pot and sauté until softened, about 5 minutes.
Add the crushed tomatoes, white wine, beef broth, bay leaves, thyme, and oregano. Stir well.
Return the veal shanks to the pot and spoon some of the sauce over them.
Cover the pot with a tight-fitting lid and transfer it to the oven.
Cook the Osso Buco in the oven at 350°F (175°C) for 2-3 hours, or until the meat is very tender and falling off the bone.

For the Gremolata:

In a small bowl, mix together the chopped parsley, lemon zest, and minced garlic.
For the Creamy Polenta:

In a medium saucepan, bring the water to a boil.
Gradually whisk in the polenta, stirring constantly to prevent lumps.
Reduce the heat to low and continue to cook the polenta, stirring frequently, for 20-25 minutes, or until it thickens.
Stir in the grated Parmesan cheese and heavy cream.
Season with salt and pepper to taste.

To assemble:

Serve the Osso Buco over a bed of creamy polenta.

Top with a spoonful of gremolata.