Roasted Red Pepper & Sun Dried Tomato Dip

cream cheese (softened)

mayonnaise

yellow onion (finely chopped)

garlic cloves (minced)

sun-dried tomatoes (packed in oil, chopped)

chopped roasted red bell peppers (about 1 1/2 peppers)

shredded mozzarella cheese

shredded Italian cheese blend

shredded Parmesan cheese, divided