I used the recipe in the Penzey's catalog and made some adjustments based on what I had on hand, and every time I have made it it is a bit different based on the cheeses I use. As easy as a grilled cheese sandwich, but better!
5 tbsp butter
1 cup shredded cheddar cheese (Monterey Jack also works well)
1 cup shredded swiss cheese
1/4-1/3 cup mayonnaise (I used light with great results)
1 bunch green onions chopped (including the green parts)
1 tsp sweet or hot curry powder (your choice, but use Penzey's of course)
1-2 garden tomatoes
Split and toast the muffins, then butter and place on cookie sheet. Mix the cheeses, green onions curry powder and mayonnaise gently until well-combined. Slice the tomatoes in uniform slices and dry off with paper towels,placing a tomato slice on each muffin. Cover the tomato slices with the cheese mixture and broil for 4-8 minutes until brown and bubbly. Now try not to eat all 12 yourself!!