Lay the bread slices on a work surface. Spread one side of each slice generously with Challenge Spreadable Butter with Extra Virgin Olive Oil.
Flip the bread over so the buttered sides face down. Layer the cheeses evenly over 2 slices of bread, then top with the remaining bread, buttered sides facing out.
Heat a large skillet over medium-low heat. Add the sandwiches and cook for about 3 to 4 minutes per side, pressing lightly with a spatula, until the bread is deeply golden and crisp and the cheese is melted.
If the bread is browning before the cheese is fully melted, reduce the heat to low and cover the skillet for 1 to 2 minutes.
Transfer to a cutting board, let rest for about 1 minute, then slice and serve immediately.