Preheat your oven to 190°C.

In a skillet over medium heat, melt garlic butter and sauté onions and bell peppers until softened.

Add the thinly sliced beef to the skillet, season with salt and pepper, and cook until browned.

Slice the Italian bread lengthwise and scoop out some of the insides to create space for the filling.

Fill the bread with the beef, onion, and pepper mixture.

Top generously with shredded provolone cheese.

Bake in the preheated oven for 15-20 minutes, or until the cheese is melted and bubbly.

Remove from oven and let cool slightly before slicing. Garnish with fresh parsley and serve warm.