I saw a recipe similar to this, made quite a few changes and made it my own. Love these on a hot summer day, but good year round. I also roast my own peppers as they have much more flavor than the bottled ones, however if you are in a hurry or don't want to take the extra steps to roast by all means use the easy way and buy the bottled peppers.
portabella mushroon (stems and fins removed)
red bell peppers-roasted
1 large bunch
1Roast red and pasilla peppers until skins are blackened, then place in paper bag for 30 minutes to steam. Optional- Bottled Roasted Red Bell Peppers
2clean stems and fins from mushrooms. I use a teaspoon and carefully remove the fins. Freeze the stems to use in stock later.
4after steaming peppers, clean skins, seeds and stems from peppers ( DO NOT RINSE IN WATER THIS WASHES ALL THE OILS AND FLAVOR DOWN THE DRAIN)
5Place mushrooms on grill cap side up until they start to warm through. Flip over and fill inside with a blend of both roasted peppers
6when mushrooms are warm to touch add 2 slices of swiss cheese to each ( I use Alpine Lace which is a low fat cheese )