Is there anyone who doesn't like grilled cheese? When my daughter was a baby, my good friend Andrea (who has a daughter the same age) made grilled cheese sandwiches for the two of us when we had our weekly visit at her house. There was something so warm and comforting about eating buttery grilled cheese while watching our babies attempt to crawl, or build houses out of blocks. Andrea moved away when our girls were about 10 years old, but hanging out with her and eating are some of the fondest memories of our day to day friendship.
While throwing vegetables into grilled cheese sandwiches has been a habit of mine for a long time, my grilled cheese life was transformed by Christina Tosi's genius grilled cheese that uses mayo on the outside of the bread instead of butter. I'll frequently use leftover vegetables from the night before, but I particularly like the combination of butter sautéed mushrooms and super sharp aged Gruyere. (If you haven't made the leap to aged Gruyere, do; it's transformative.)
So this recipe is a tribute to my long friendship with Andrea--with gratitude to Christina Tosi, who made my grilled these life so much better. —drbabs
3-4 mushrooms, sliced thin (regular white mushrooms are OK, but use what you like)
small shallot, minced
kosher salt and fresh ground black pepper to taste
Heat butter in non-stick skillet over medium heat until it begins to foam. Add mushrooms, thyme and shallot with a generous pinch of kosher salt, and cook, stirring occasionally, until mushrooms are lightly browned, shallot is transparent, and most of the liquid has evaporated. Taste and adjust seasoning. Remove mushroom mixture from sauté pan, and set aside. Wipe out sauté pan, and place it back on the stove over medium-low heat.
Spread mayonnaise over both slices of bread. Flip one slice over. Place about half the Gruyere onto the bread. Top with the mushroom mixture (You may or may not use it all), and top the mushrooms with the second slice of bread, mayonnaise side up.
Place sandwich in the pan and cook until the bottom side is golden--5-7 minutes. Flip the sandwich over and cook the other side. Remove the sandwich from the pan, let it cool a bit, then cut it in half (oozy, melty) and enjoy.