Heat olive oil in a medium saucepan over medium heat. Add garlic and cook until fragrant, about 30 seconds. Stir in crushed tomatoes, oregano, red pepper flakes if using, and salt. Bring to a gentle simmer, reduce heat to low, and cook uncovered for 15 minutes, stirring occasionally, until slightly thickened. Remove from heat and stir in fresh basil. Keep warm or serve at room temperature.

Slice the mozzarella block into 16 sticks, about 0.5 by 0.5 by 4 inches. Arrange on a plate and freeze for 20 minutes - this is crucial to prevent cheese from leaking during frying.

In a shallow bowl, whisk together breadcrumbs, Parmesan, and garlic powder. Place flour in a second shallow bowl and beaten eggs in a third.

Working one at a time, dredge each frozen cheese stick in flour, shaking off excess. Dip in egg, then coat in breadcrumb mixture, pressing gently to adhere. For extra insurance against blowouts, repeat the egg and breadcrumb coating for a double layer. Place breaded sticks on a wire rack.

Pour vegetable oil into a heavy pot to a depth of 2 inches. Heat over medium-high until a thermometer registers 350F. Maintain this temperature throughout frying - too cool and they'll get greasy, too hot and the cheese will explode.

Fry mozzarella sticks in batches of 4 to 5, turning occasionally, until deep golden brown, about 2 to 3 minutes total. Transfer to a wire rack set over a baking sheet to drain. Let rest 1 minute before serving - the cheese inside will be molten.

Arrange hot mozzarella sticks on a platter with warm marinara for dipping. Garnish with extra fresh basil if desired.