Prepare the Filling:
In a small bowl, combine the chopped spinach, shredded mozzarella cheese, crumbled feta cheese, ricotta cheese, and chopped sun-dried tomatoes.
Optional: Add a pinch of garlic powder, dried oregano, or red pepper flakes to the cheese mixture for added flavor.
Assemble the Sandwich:
Spread softened butter (or brush olive oil) on one side of each slice of bread.
Place one slice of bread, butter-side down, in a skillet or on a griddle over medium heat.
Spread the cheese and spinach mixture evenly over the bread in the skillet.
Top with the second slice of bread, butter-side up.
Grill the Sandwich:
Grill the sandwich for 2-3 minutes per side, or until the bread is golden brown and the cheese is melted and gooey.
Use a spatula to carefully flip the sandwich.
If the bread is browning too quickly, reduce the heat slightly.
Serve:
Remove the grilled cheese sandwich from the skillet and let it cool for a minute or two before cutting in half.
Serve immediately and enjoy!
Tips and Notes:
