This recipe marries two of my favorite guilty pleasures: grilled cheese sandwiches and a classic Southern pimento cheese spread. Mayonnaise is the magic ingredient here. It makes the cheesy filling incredibly gooey and a thin smear on the outside gives the bread a crispy, golden crust. Per the name, pimento cheese is traditionally made with jarred pimento peppers, but I like to add a bit of tang and use pickled cherry peppers in their place. The acidity of the pickles cuts through the richness of the cheeses. This recipe makes a quart of pimento cheese, which is more than you’ll need for four sandwiches. Use any leftovers to make more sandwiches or serve with Saltine crackers and cut up vegetables during cocktails.
In the bowl of a food processor, pulse the cream cheese with the mayo until smooth. Add the pimentos, scallions and hot sauce and pulse until just combined. Add the shredded cheeses and pulse until incorporated, but still slightly chunky. Season with pepper and hot sauce to taste. Transfer to 1-quart jar for storage.
Heat a non-stick griddle or large cast-iron skillet over moderately low heat. Top 4 slices of bread with 3 tablespoons of pimento cheese and spread in an even layer. Close the sandwiches and spread a thin layer of mayonnaise on the top slice of bread. Cook mayonnaise side down until golden brown, about 3 minutes. Spread a thin layer of mayonnaise on the top slice of bread, flip and continue cooking until golden brown all over and the cheese is melted, about 3 minutes more. Transfer sandwiches to a cutting board and let rest for 2 minutes. Cut in half and serve.
MAKE AHEAD: The pimento cheese can be refrigerated for up to 1 week.