Breadcrumbs: In a large pan over medium heat melt in 1 heaped tbsp butter. Add Panko breadcrumbs and coat in the butter. Continue to toast the breadcrumbs, using a wooden spoon to move them about frequently, until nice and golden. Pour in 1 of your shallow dishes and leave to cool.
Marinara Sauce: In the same pan over medium heat warm 1 tbsp extra virgin olive oil. Add in onion and fry until it begins to soften and just begins to pick up colour. Add garlic and fry another 1-2mins. Pour in passata and shake the jar out with a splash of water. Add in basil, oregano and seasoning to taste. Depending on the quality of your tomatoes you may need to add a pinch of sugar to balance out the acidity. Leave on a gentle simmer for 20mins, or until nicely thickened.
Pound Chicken: Lay cling film over chicken breast and pinch around it (just so no juices escape). Pound until they're around 1/4-1/2" thick. You want them as thin as you can get them without the breast breaking apart. Slice off any stray pieces around the edges.
Coat Chicken: In a small pot combine 1 tsp salt & garlic powder, 3/4 tsp oregano and 1/2 tsp black pepper. Pour half in a shallow dish with your flour and the other half in a shallow dish with breadcrumbs and parmesan. One by one coat a breast in the seasoned flour, then into egg, then into the seasoned breadcrumb/parmesan mixture. Really make sure you completely coat the chicken at each stage, namely the last stage. Place on a lightly oiled wired rack above a baking tray. Repeat with remaining breasts.
Bake (see notes for frying): Bake in the oven at 425F/220C for 10-12mins until the chicken begins to crisp, take out and carefully flip. Rotate tray and place back in the oven for another 5-10mins or until the chicken is golden crispy. At this point it should just be cooked through.
Top Chicken: Take chicken off wire rack and place on the tray. Spread over a good dollop or sauce, top with two wedges of mozzarella each, then sprinkle with parmesan. Place back under the grill and broil on high until the cheese goes golden and gooey.
Serve: sprinkle over fresh basil and serve over spaghetti or with chips/fries and side salad!