11. Mix ground beef, breadcrumbs, Parmesan, egg, garlic, oregano, salt, and pepper in large mixing bowl. Blend thoroughly without overmixing.
22. Form mixture into 8 uniform meatballs, approximately 2 ounces each. Ensure consistent sizing for even cooking.
33. Brown meatballs in large skillet over medium-high heat until exterior is golden and internal temperature reaches 160°F, about 8-10 minutes. Rotate frequently to prevent burning.
44. Warm marinara sauce in separate saucepan. Add dried basil and red pepper flakes. Simmer gently.
55. Once meatballs are cooked, transfer directly into marinara sauce. Allow to absorb flavors for 3-4 minutes.
66. Split submarine rolls lengthwise. Lightly toast inner surfaces until golden and crisp.
77. Arrange 2 meatballs per roll. Spoon additional marinara sauce over meatballs.
88. Sprinkle mozzarella cheese on top. Allow residual heat to slightly melt cheese.
99. Garnish with chopped parsley. Serve immediately.