Both a breakfast and supper sandwich. i've been really impressed with some Oscar Meyer American style bacon I've recently discovered in the UK. It's a sort of dry cured smokey streaky bacon, thickly cut that you can fry, and it produces lots of fat which I pour off and save for other things.
I chop the bacon up and fry it with some fine chopped red onion, let it cool, mix it with some grated Red Leicester cheese which I top on some toast that I've buttered and put a smear of Dijon mustard on and then put it into an airfryer for a minute or two. That cooks the toping and crisps the toast. It's a sort of croque but with no egg in the mix, so no souffle.
I keep a cup of the topping in the fridge for another night. It is lovely.