01 -
In a skillet over medium heat, warm olive oil and sauté the minced garlic for 1 minute. Add the frozen spinach, salt, and pepper. Cook while stirring until the spinach releases its moisture and becomes dry. Remove from heat.
02 -
Spread butter on one side of each bread slice. Place slices butter-side down to begin assembling.
03 -
On two slices, layer half of the shredded mozzarella, followed by crumbled feta and the cooked spinach. Optionally, sprinkle with crushed red pepper flakes. Add the remaining mozzarella, then top with the other bread slices, butter side up.
04 -
Heat a skillet over medium-low heat. Grill the sandwiches until the bread is golden and crisp, and the cheese is melted, flipping once during cooking.
05 -
Slice the sandwiches in half and serve hot.