Penne alla Vodka Recipe

Ingredients

• tablespoons unsalted butter
• medium yellow onion, diced
• medium cloves garlic, thinly sliced
• red pepper flakes
• Kosher salt
• One 4 1/2-ounce tube concentrated tomato paste or 6-ounce can tomato paste
• One 14 1/2-ounce can whole peeled tomatoes
• heavy cream
• pound short tubular pasta, such as rigatoni or penne
• vodka, plus more if desired
• ounces grated Parmigiano-Reggiano, plus more for serving