The invention of the grilled cheese sandwich is arguably the greatest thing since, well, sliced bread. And while folks have been toasting bread with cheese since Ancient Roman times, the American variety took off in the 1920s with the invention of the first bread slicer.

Just before that J.L. Kraft and Brothers began making its processed cheese, or as the English called it, rat trap cheese. They are, of course, partial to their cheddar. But here in the States, the grilled cheese sandwich took off with these two inventions, and today they’re considered classic comfort food. If you’re in the mood to be fancy, add some sliced apples, bacon, or brie.

But whatever you’re craving on National Grilled Cheese Sandwich Day, enjoy a crunchy, melty morsel of comfort food deliciousness, with or without the rat trap cheese.

Today we also celebrate: National Education and Sharing Day, National Only Child Day, National Big Wind Day, National Colorado Day, National For Twelves Day, and National Licorice Day.