Grease two 8x4-inch loaf pans with olive oil. Sprinkle with panko and tip to coat evenly. Set aside.
In a large bowl or the bowl of a stand mixer fitted with a kneading hook, whisk together the water and yeast. Let stand a few minutes. Add oil, sugar, salt, Italian seasoning, garlic powder and about 4 cups of the flour. Mix and then knead, adding more flour in small increments, as necessary, to form a soft, moist dough. Cover bowl with plastic wrap and allow to rise for 45-60 minutes, or until almost doubled.
Meanwhile, prepared the filling by stirring together all the filling ingredients. Set aside.
When dough has risen, remove to a flour dusted work surface and gently deflate. Divide dough into two even pieces. Roll one piece of dough in to a rectangle about 1/2 inch thick. Spread 1/2 of the filling over dough, then roll up dough jelly-roll style.
Cut jelly roll in to 8-10 slices. Snug slices next to each other in prepared loaf pan. Repeat with remaining piece of dough and remaining filling.
Beat egg in a small bowl, then brush over dough. Sprinkle with garlic powder, salt and pepper, then scatter a bit more Parmesan and mozzarella over top. Drizzle with a bit of olive oil, over-top. Cover with plastic wrap and let rise until dough is puffy, about 45-60 minutes.
Preheat oven to 375 F. Bake 20 minutes at 375 F., then reduce oven to 350 F. and bake for a further 20-30 minutes, or until nicely browned and cheese is melted.
Notes
Be sure to read the notes above this Recipe Card, for more tips on making this recipe.