01 - Gently mix fresh blueberries with honey and lemon zest in a small bowl until evenly coated.
02 - Spread an even layer of softened cream cheese on one side of each bread slice.
03 - Sprinkle shredded mozzarella over half of the bread slices, covering the cream cheese.
04 - Spoon the blueberry mixture onto the mozzarella-covered slices, spreading evenly.
05 - Place the remaining bread slices on top, cream cheese side facing in, to form sandwiches.
06 - Spread softened butter on the outer surface of each assembled sandwich.
07 - Heat a nonstick skillet over medium heat. Place sandwiches into the skillet and cook for 3 to 4 minutes per side, pressing gently, until bread is golden brown and cheese is melted.
08 - Remove sandwiches from the skillet, allow to cool slightly, slice each in half, and serve warm.