This is one luxurious grilled-cheese sandwich. With the onions and the tomatoes and the mustard I thought for a moment I was eating a cheese-pork tenderloin sandwich.
You can easily make these in a skillet. We gave them a whirl on a pancake griddle smeared with olive oil.
You’ll need a few tomatoes and an onion or two. You’ll need to make really thin slices with either a mandolin or a knife. You want the slices to break apart when you sink your teeth into this sandwich. No one likes a sandwich so chunky that you pull all of the guts out of it when you take a bite.
Here’s a rough idea of what you need to get them started.
2 tomato slices per sandwich.
2 onion slices per sandwich
2 Gouda slices per sandwich ( I bought a block of cheese and took it to the deli guy to get him to slice it.)
2 pieces of bread per sandwich–duh?
2 tbsp olive oil for the griddle or pan.
Mustard dipping sauce made from equal parts sour cream and honey Dijon mustard. We used 2 tbs of each for four sandwiches.