Evenly spread butter on one side of each bread slice, placing bread, buttered-side-down on clean work surface or sheet pan. Equally distribute shredded Toma and Gouda on 4 slices of bread. Top with remaining 4 bread slices, buttered-side-up.
Heat a non-stick skillet over medium heat. Add sandwiches to pan. Gently press sandwiches with spatula as they cook, flipping every couple minutes to ensure even cooking. Cook until cheese melts and bread is toasted.
