INSTRUCTIONS
1
Halve and pit the avocado. Scoop the flesh into a medium bowl and mash. Stir in the onion, cilantro, jalapeño, lime juice, and ¼ tsp kosher salt.
2
Divide the cheeses between two slices of bread. Top with the other slices of bread to make two sandwiches.
3
Melt half of the butter in a 12-inch heavy-duty skillet over medium-low heat. Add the sandwiches and cook until golden brown on one side, 3 to 4 minutes. Flip, add the remaining butter, and cook, lifting the edges of the bread to allow the butter to run under and adjusting the heat as necessary, until the cheese has melted and the other side is golden brown, another 3 to 4 minutes.
4
Transfer to a cutting board and open the sandwiches. Spread about ¼ cup guacamole on half of each sandwich and top with the bacon. Reassemble, slice in half, and serve.