In a large mixing bowl, combine the cold ground beef, hydrated rice flour slurry, eggs, Parmigiano-Reggiano, garlic paste, parsley, salt, black pepper, oregano, red pepper flakes (if using), and Worcestershire sauce. Mix by hand using a folding motion only — do not squeeze or knead. Stop the moment no dry pockets remain. Overworking compresses the protein matrix and produces a rubbery crumb.
3 tablespoons superfine white rice flour, 3 tablespoons whole milk, 2 large eggs, 1.5 oz finely grated Parmigiano-Reggiano, 4 cloves garlic, minced to a paste, 2 tablespoons fresh flat-leaf parsley, finely chopped, 1.5 teaspoons kosher salt, 0.75 teaspoon freshly ground black pepper, 0.5 teaspoon dried oregano, 0.25 teaspoon red pepper flakes, 1 teaspoon Worcestershire sauce