Preheat oven to 400 F
In a small bowl mix together the unsalted butter, minced garlic, parsley, chives, salt and pepper. Set aside.
In another small bowl mix together all cheeses.
Place slices of sourdough on cutting board and butter bread (face side up). Pile mixture of cheeses onto 4 slices of sourdough and place buttered piece on top. Butter top side of bread and set aside.
Heat a large oven proof skillet over medium high heat. Place sandwich (butter side down) and cook until golden brown. Butter top piece of bread and flip over to brown in skillet. Place skillet into preheated oven for about 5 minutes or until cheeses are fully melted.