Ingredients:

  • 12 slices thick-cut sourdough bread (approx. 1/2 inch thick)
  • 0.5 cup mayonnaise
  • 3 tbsp unsalted butter, melted
  • 8 oz sharp white cheddar, freshly grated
  • 8 oz Gruyère cheese, freshly grated
  • 0.125 tsp garlic powder
  • 0.125 tsp smoked paprika

Instructions:

  1. Preheat your oven to 400°F (200°C). Place your baking sheet inside while it heats. Note: A hot pan starts the searing process the moment the bread touches it.
  2. In a small bowl, whisk together the 0.5 cup mayonnaise, 3 tbsp melted butter, 0.125 tsp garlic powder, and 0.125 tsp smoked paprika.
  3. Lay out the 12 slices of sourdough and spread the mayo butter mixture generously on one side of each slice.
  4. Remove the hot baking sheet from the oven and carefully line it with parchment paper. Place 6 slices of bread, fat side down, onto the parchment. Listen for the sizzle as they land.
  5. Distribute the 8 oz of grated sharp white cheddar and 8 oz of Gruyère evenly across the 6 slices. Note: Keep the cheese slightly away from the very edges to minimize leakage.
  6. Place the remaining 6 slices of sourdough on top, fat side up.
  7. Slide the tray into the center rack of the oven and bake for 6 minutes until the bottom edges look golden and lacy.
  8. Carefully flip each sandwich using a wide spatula. Note: The top side will now be in contact with the direct heat of the pan.
  9. Return to the oven for 4-6 more minutes until the bread is a deep mahogany gold and the cheese is bubbling.
  10. Let the sandwiches sit on the tray for 2 minutes before slicing. This allows the molten cheese to set slightly so it doesn't all run out when you cut it.