- Heat a cast iron pan over low-medium heat.
- Spread aioli generously over one side of 2 pieces of bread and lay them down, aioli side down, into the warmed pan. Line the tops with half of the cheese. Top the cheese with the tomato slices, and then top those with the remaining cheese.
- Spread aioli generously over one side of each of the remaining slices of bread. Place the slices, plain side down, on top of the cheese. Allow to cook for 2-3 minutes, or until bread has browned and cheese has begun to melt. Flip and cook for an additional 2-3 minutes until the other side is also browned.
- Remove and cool slightly before serving.