Mince garlic and add it to a pan with the olive oil.

Cook over medium-low heat for 1-2 minutes, or until it begins to soften

Add the frozen spinach, turn the heat up to medium, and cook for about 5 minutes, or until heated through the most of the excess moisture has evaporated away. Season lightly with salt and pepper.

Cut the rolls in half, and add mozzarella and feta to the bottom half of each roll.

Divide the cooked spinach between the two sandwiches.

Place the top half of the ciabatta roll on the sandwiches and transfer them to a large non stick pan. Let toast for a few minutes on medium-low. Flip carefully and toast other side with lid on pan to melt the cheese.