Directions: In a small pan, heat olive oil over medium heat; add onions and spinach sauté until soft. In a medium bowl, combine the onions and spinach with artichokes, sour cream, Parmesan cheese, and Salsa di Parma Bread Dip; mix well.
To make sandwiches
Butter the outsides of each slice of bread and lay butter side down on a piece of parchment paper or cutting mat. Spread ¼ of artichoke mixture on each of the 4 slices of the buttered bread. Lay basil leaves over the artichoke mixture then add 2 slices of mozzarella. Spread mayonnaise on remaining 4 slices of bread; put mayonnaise side down over mozzarella.
Heat a large skillet over medium heat, then cook the sandwiches for about 2-3 minutes until golden on the bottom. Flip the sandwiches and cook for another 2-3 minutes.