This is an easy, colourful, and delicious, filling, and spicy vegetarian dish which can be made vegan by omitting the butter. Serve with a side salad mixed with some sun-dried tomato strips, cherry tomatoes, and whatever herbs you used in the filling.
If you don't have a small enough baking dish to hold your peppers standing up, try linking them 2-by-2 with a toothpick or small cocktail stick inserted near the top. Also, as is usual with any recipe, try different herbs - marjoram works well, and you can try basil, thyme, sage, etc. You can also add 3 finely chopped chestnut mushrooms for an earthy, meatier taste (add with the cherry tomatoes in step 5).
I like to use yellow or orange peppers for a nice colour contrast with the green and red of the filling.