In the same iron skillet, where the Braciole was seared, warm the butter on medium heat. Once the butter is melted, add the onions and garlic and cook until the onions are translucent and the garlic is fragrant.
Now add the white wine and cook until the alcohol is removed, 4-5 minutes.
Now add the tomato paste and cook for another few minutes, 5-6 minutes.
Add the crushed tomatoes and stir together.
Add the spices and season as needed with salt and ground pepper.
Notes
You do not want to clean your cast iron skillet after cooking the Braciole because that meat fond. The fond, browned bits of meat stuck to the bottom of the cast iron) is great for building the sauce. However, if you have a lot of oil in your skillet, remove some that oil prior to adding the butter.
This sauce could be made on it's own and if you take that route, simmer for at least 1 hour on your stovetop.