Now I tried to tomatoes two different ways. The first was to put them in a pan with a touch of olive oil and cook till they're a bit soft. Or rather, softer than usual for a tomato! I also used them freshly sliced...either way was good.
I toasted some bread. you could use a nice looking bun of some sort but all I had was sliced bread. I spread a bit of mayo, loaded one side with the onions.
I put a slice or two or tomato on each sandwich, covered it with mozzerella cheese and sprinkled it with some basil. On the basil note, I've read that dried basil keeps it's flavor better if stored in larger pieces. I will say that my basil that I've just recently dried and stored as whole leaves (more or less) in a spice jar seems to have more flavor than the basil I've bought already broken into tiny pieces. I will also say that the extra flavor of the basil really made this for me. I popped it in the oven to melt the cheese a bit. I also tried the microwave and didn't observe a huge difference.