Ingredients
2 tablespoons olive oil8 tablespoons butter, softened, divided 4 large portobello mushroom caps, gills removed and sliced1/8 teaspoon salt1/8 teaspoon pepper3 tablespoons mayonnaise 3 tablespoons finely shredded Manchego or Parmesan cheese1/8 teaspoon onion powder8 slices sourdough bread4 ounces Brie cheese, rind removed and sliced1/2 cup shredded sharp white cheddar cheese 1/2 cup shredded Monterey Jack cheese1/2 cup shredded Gruyere cheese 2 teaspoons minced fresh thyme
Preparation
In a large cast-iron or other heavy skillet, heat olive oil and 2 tablespoons butter over medium-high heat. Fry mushrooms in a single layer until golden and beginning to crisp, turning halfway through, 10-12 minutes. Sprinkle with salt and pepper. Remove mushrooms; wipe out skillet.
Spread 3 tablespoons butter on 1 side of each slice of bread. Place bread, butter side down, in same skillet over medium-low heat; toast until golden brown, 2-3 minutes; remove. In a small bowl, combine cheddar, Monterey Jack and Gruyere. In another bowl, mix together remaining 3 tablespoons butter, mayonnaise, Manchego cheese and onion powder.
To assemble sandwiches, top toasted side of 4 bread slices with mushrooms; sprinkle with fresh thyme; add sliced Brie. Sprinkle cheddar cheese mixture evenly over Brie. Top with remaining bread slices, toasted side facing inwards. Spread the butter-mayonnaise mixture on the outsides of each sandwich. Place in same skillet and cook until golden brown and cheese is melted, 5-6 minutes on each side. Serve immediately.
