In a small bowl, mix together the softened butter, granulated sugar, brown sugar, and honey until smooth.
Take two slices of bread and add a generous layer of mozzarella cheese between them to create a sandwich. Repeat with the remaining bread and cheese.
Spread a thick layer of the honey butter mixture over the outside of each sandwich, coating both sides.
Heat a non-stick pan over medium-low heat.
Toast the sandwiches until the bread is deeply golden and caramelized and the cheese has fully melted.
Remove from heat, slice in half, and serve warm while the cheese is still perfectly gooey.
Serves 2. A sweet-and-salty snack: crispy honey-butter-glazed bread stuffed with gooey melted mozzarella. From @ammirene, via @eatinghealthygram on Instagram.
