Place 2 slices of white bread on a plate.

Using a butter knife, spread 2 tsp of softened butter on each piece of bread, buttering only one side of each slice.

Place a pan or skillet over medium-low heat.

Once the pan is heated, place one slice of bread, buttered side down, onto the pan.

Lay 1 slice of cheddar cheese on top of the bread. Sprinkle 2-3 tbsp of mozzarella cheese over the cheddar cheese.

Lay another slice of cheddar cheese on top of the shredded mozzarella cheese.

Place the other slice of bread on top with butter side up.

Grill the sandwich on each side for 3-4 minutes until the bread is lightly browned.

Flip the sandwich bread once one side of the bread is done. Use a spatula to gently press down on the sandwich to ensure even grilling.

Once both sides of the bread are brown, melt the cheese, remove the sandwich from the heat, and transfer it to a plate.

Slice the sandwich in half to reveal the gooey cheese inside.