Creating the perfect Feta Grilled Cheese Sandwich with Spinach is a breeze when following these simple steps:

1. Prep the Spinach: In a skillet over medium heat, add the olive oil or butter. Once hot, add the chopped spinach. Sauté until wilted, approximately 2-3 minutes.
2. Season: Add salt and pepper to taste. For added flavor, include garlic powder or red pepper flakes if desired. Set aside.
3. Prepare the Bread: Lay out the slices of bread on a clean surface.
4. Assemble the Sandwich: On two slices of bread, layer a mix of crumbled feta cheese and sautéed spinach. Top with a generous amount of shredded mozzarella cheese.
5. Top It Off: Place the other two slices of bread on top, creating two sandwiches.
6. Grill the Sandwiches: In the same skillet used for spinach, toast the sandwiches. Grill each side until golden brown and crispy, about 3-4 minutes per side. If needed, press down gently with a spatula to ensure even browning.
7. Melt the Cheese: Cook until the mozzarella is fully melted and gooey.
8. Slice and Serve: Once ready, remove the sandwiches from the skillet, let them cool for a moment, then slice in half.

These straightforward steps will guide you to create an amazing Feta Grilled Cheese Sandwich with Spinach that is sure to delight your taste buds.