01 -
Arrange bread slices flat on a cutting board. Evenly spread softened butter on each slice.
02 -
Place half of the bread slices butter-side down. Spread 1 to 2 tablespoons basil pesto on each, then layer with mozzarella slices, gouda slices, and grated Parmesan. Top with tomato slices and season with salt and pepper.
03 -
Cover each prepared half with a remaining slice of bread, butter-side up. Working in batches, cook sandwiches in a large nonstick skillet over medium heat for 3 to 4 minutes per side, until golden brown and cheese is melted.
04 -
Transfer grilled cheese to a serving plate and serve immediately while warm.