Preheat the oven to 425°F (220°C). Line a baking sheet with parchment paper or foil for easier cleanup. Using a serrated knife, slice the baguette in half lengthwise so you have two long halves. If you prefer pull-apart pieces, score the inside of each half in a crosshatch or make evenly spaced diagonal cuts about 1/2 inch apart without cutting through the crust.

Make garlic butter

In a small bowl, combine the softened unsalted butter and olive oil. Add the minced garlic, finely chopped parsley, salt, black pepper, and lemon juice (if using). Mix thoroughly until smooth and evenly distributed. Taste and adjust salt or garlic as desired.

Assemble bread

Spread the garlic butter mixture evenly over the cut sides of the bread, making sure to get into cuts or score lines so flavor penetrates. Place both halves, buttered side up, on the prepared baking sheet, leaving space between them.

Cheese Topping

Add cheeses

Combine the shredded mozzarella, grated Parmesan, and optional cheddar/provolone in a bowl and toss to mix. Evenly sprinkle the cheese mixture over the buttered bread halves, pressing lightly so it adheres. If making pull-apart, be sure cheese gets into the cuts so each piece is cheesy.

Season

Sprinkle the dried oregano and red pepper flakes evenly over the cheese for aromatics and a touch of heat. If you like more herb flavor, add a bit more chopped fresh parsley on top.

Bake & Finish

Bake

Place the baking sheet on the middle oven rack and bake for 8–12 minutes, until the cheese is melted and bubbling and the edges of the bread begin to turn golden. Baking time will vary with oven and bread thickness; check at 8 minutes to avoid overbrowning.

Broil for color (optional)

For a golden-brown top, switch the oven to broil for 1–2 minutes, watching closely so the cheese doesn't burn. Remove as soon as the cheese has attractive browning spots.

Rest and serve

Let the cheesy garlic bread rest on the baking sheet for 2–3 minutes to set. If you scored or sliced the bread beforehand, separate pieces now. Garnish with additional chopped fresh parsley if desired. Serve warm.