Heat olive oil and butter in a pan on low/medium heat until the butter has melted.
Add garlic, Italian seasoning, and red pepper flakes to the pan and cook for 2-3 minutes until garlic is fragrant. Stir frequently, so the garlic does not brown or burn.*
Push down the middle of the bread on both sides and place on a baking sheet.
Baste oil and herb mixture on top of the bread and spread shredded cheese evenly over top. Add Parmesan if using.
Cook in the oven for 9-11 minutes, until the degrees start to turn golden brown.
Top with parsley if desired.
Cut in slices and serve immediately.
Video
Notes
*Sauce can be made ahead and stored in a refrigerator for up to 5 days. To use, microwave until mixture is melted then baste on top of bread as normal.