I get an "F" for presentation but an "A" for taste on this recipe I got from fatfreevegan.com http://blog.fatfreevegan.com/2006/06/portabellas-stuffed-with-pesto-mashed.html
A few potatoes, cooked and mashed
A few Portabellas (I made one per person) washed and cleaned out
Garlic, pressed or diced
Make a pesto with the walnuts, garlic and basil in food processor (I used my blender because I don't have a food processor.) Add to the mashed potatoes, incorporating some non-dairy milk if needed to make creamy. Fill washed and emptied portabellas, sprinkle with nutritional yeast and cook at 375 for 15-20 minutes until starting to brown.