How To Make A Giant Grilled Cheese

Gather the ingredients.

If your loaf is very large (i.e. Pullman) then slice off the top 2 inches to make the loaf more square than rectangular. If your loaf is average-sized, slice 1/2-inch to an inch off the top.

Slice the loaf in half lengthwise, Open the two halves like a book, so the interior of each half is facing you.

Place a baking sheet on the middle rack in the oven, and preheat to 350 F.

Using a spoon, dig an indentation about 1/2-inch deep along the crust edges of each half, then remove a shallow layer of the bread's interior by gently pulling it out towards you with your fingers. This will give the cheese a small well to melt into. Reserve the scooped-out bread to make breadcrumbs.

Cut a sheet of parchment paper that will fit both halves of the loaf and place it on your work surface. Flip both halves of the bread over so the exteriors are facing you.

Generously spread the tops of the loaf halves (not the interior section with the scooped-out wells) with mayonnaise, then flip over once more and place both halves mayonnaise-side down on the parchment.

Layer the cheese slices into the scooped-out wells in each half: American first, then cheddar, then mozzarella.

Remove the baking sheet from the oven, then quickly transfer the halves from the parchment to the baking sheet, using a spatula if necessary.

Bake for 18-20 minutes, or until cheese on top of both halves is bubbly and browning.

Remove the baking sheet from the oven, then carefully flip the top half of the bread onto the bottom to make a sandwich, and transfer the whole thing to a cooling rack. Let rest for 10 minutes.

Make the first slice in the middle (and check out that cheesy pull), then let rest for another 5-10 minutes before slicing individual sandwiches out from the middle of each half of the giant grilled cheese. This will ensure even distribution of cheese within each slice.