Preheat oven to 180c/350f
Remove crusts from bread, so that each slice weighs 30g/1ozz
Using a rolling pin, roll over each slice of bread to flatten.
Spray both sides of bread with spray oil or spread with a little butter
Push down into a muffin tray to form bread cups.
Place in oven and bake for approx 20mins until lightly golden
Add ground beef, salt, pepper, garlic and onion powder to a bowl and mix well to combine.
Form into 8 meatballs (they should be about the right size to fit in each bread cup)
Place on a baking tray lined with parchment and place in the oven and bake for approx 10-15mins to lightly brown.
Once bread cups are ready and meatballs lightly browned.
Add the meatballs to bowl and cover well with marinara sauce.
Place one meatball with sauce into each toasted bread cup and then top with mozzarella cheese.
Repeat with all 8 cups.
Place back in the oven for approx 15 mins, until cheese is melted and golden.
Top with a little chopped fresh Italian parsley or basil.