Preheat the oven. Set it to 425°F (220°C).
Line a baking sheet with foil or parchment for easy cleanup.
Prep the bread. Slice the loaf lengthwise into two long halves. Place cut-side up on the baking sheet.
Make the garlic butter. In a bowl, mix softened butter, olive oil, garlic, salt, pepper, Italian seasoning, parsley, and optional mayo and lemon zest. Stir until smooth and spreadable.
Toast the bread base. For extra crunch, bake the plain bread halves cut-side up for 3–4 minutes.
This helps prevent sogginess.
Spread generously. Evenly smear the garlic butter over both halves, reaching all the way to the edges so they don’t burn.
Add cheese. Sprinkle mozzarella evenly, then dust with Parmesan. Add red pepper flakes if using.
Bake. Return to the oven for 8–12 minutes, until the cheese is melted and the edges are golden.
Broil for color. Switch to broil for 1–2 minutes to brown the cheese in spots. Watch closely so it doesn’t burn.
Rest and slice. Let the bread sit for 2–3 minutes so the cheese sets slightly.
Garnish with extra parsley, then slice into thick sticks or wedges.
Serve hot. Enjoy as is, or with warm marinara for dipping.