Mushroom Grilled Cheese

Method

1. In a large cast-iron or heavy-bottomed skillet, heat 2 tablespoons olive oil and 2 tablespoons butter over medium-high heat. Saute the portobello mushrooms in a single layer until they're golden and starting to crisp, 10 to 12 minutes, turning them halfway through. Sprinkle the mushrooms with salt and pepper, then remove them from the skillet and wipe it clean.
2. Spread 3 tablespoons of the softened butter on one side of each sourdough slice. Place the bread slices, buttered side down, in the same skillet over medium-low heat. Toast them for two to three minutes until they're golden brown, then remove them from the skillet. Editor’s Tip: You'll likely need to toast the bread in batches.
3. Combine the shredded cheddar, Monterey Jack and Gruyere in a small bowl. In another bowl, mix the remaining 3 tablespoons of softened butter, mayonnaise, Manchego (or Parmesan) cheese and onion powder.
4. Arrange mushrooms on the toasted side of four bread slices. Sprinkle them with fresh thyme and layer the sliced Brie on top. Sprinkle the shredded cheese mixture evenly over the Brie, then top with the remaining bread slices, toasted side facing inwards. Spread the butter and mayonnaise mixture on the outsides of each sandwich.
5. Return the sandwiches to the skillet and cook them over medium-low heat until the bread is golden brown and the cheese melts, about five to six minutes on each side. Serve the sandwiches immediately. Editor’s Tip: If your skillet isn’t large enough for all the sandwiches, use an electric griddle or cook them in batches for perfectly browned bread.