01 - In a mixing bowl, whisk together peanut butter, soy sauce, lime juice, honey, sriracha (if desired), minced garlic, and warm water until fully incorporated and smooth. Set aside.
02 - Arrange sandwich bread slices on a cutting board. Spread a thin layer of peanut sauce over four of the bread slices.
03 - Combine shredded mozzarella and cheddar in a bowl. Distribute the mixed cheeses evenly atop the peanut sauce-covered slices.
04 - Place the remaining four bread slices over the cheese-topped slices to create sandwiches.
05 - Coat the outside of each sandwich lightly with softened butter for uniform browning.
06 - Preheat a skillet or griddle over medium heat. Grill sandwiches for 2 to 3 minutes per side, turning as necessary, until golden brown and the cheese has melted.
07 - Remove sandwiches from skillet and allow to cool briefly. Slice each into three sticks using a sharp knife.
08 - Sprinkle sticks with fresh cilantro if desired. Serve warm with reserved peanut sauce for dipping.