• Make a batch of about 20 meatballs. I used Sandra Valvassori's recipe linked in the recipe notes. To finish cooking the meatballs in tomato sauce, bake them for 12–15 minutes. Then, transfer the partially cooked meatballs to a heated tomato sauce and simmer for 10–12 minutes, or until they are fully cooked and reach an internal temperature of 165°F.

Vodka Sauce

• In a Dutch oven or large pot, melt the butter over medium heat. Add the thinly sliced onions and stir to coat them evenly in the butter. Reduce the heat to low, cover the pot, and cook for 40 minutes, stirring every 10 minutes to prevent browning. The onions should become soft and translucent.
• After 40 minutes, uncover the pot and increase the heat to medium. Stir in the tomato paste, Calabrian chili paste, salt, and sugar. Cook for about 5 minutes, stirring frequently, until the tomato paste caramelizes and deepens in color.
• Pour in the vodka and use a wooden spoon to scrape the bottom of the pot, loosening any browned bits. Stir well and cook for about 2 minutes, allowing the vodka to mostly absorb. Then, add the crushed tomatoes and simmer for 5 minutes, stirring occasionally.
• Reduce the heat to low and stir in the heavy cream and grated cheese. Mix well until the cheese has fully melted and the sauce is smooth and creamy.

Assemble Sandwich

• Preheat the broiler. Once the meatballs are out of the oven, transfer them directly into the vodka sauce. Simmer for 10–12 minutes, stirring occasionally, until the meatballs are fully cooked through.
• Place the sliced sub rolls on a baking sheet. Add the meatballs to each roll and spoon on your desired amount of sauce. Tear the burrata cheese into pieces and evenly distribute it among the subs. Broil for a few minutes until the cheese melts and the bread is lightly toasted. Finish with torn fresh basil and serve immediately.