Here's a variation on the appetizer that Jenise mentioned. It uses cream cheese instead of Gruyère, and actually replaces the olive oil in the pesto with the cream cheese. I made a triple batch of them for a "Drink Up The Cellar" party we had last night (theme: use up our older wines before they go over the hill). They disappeared very quickly. One attendee begged for the recipe.
I found it on http://www.savorynothings.com/pesto-stuffed-mushrooms/
Pesto Stuffed Mushrooms
12 medium sized white mushrooms (I used brown cremini mushrooms)
3.5 oz low fat cream cheese
1 cup packed basil leaves
1 tablespoon pine nuts
¼ cup shredded Parmesan
2 tablespoons bread crumbs (I used panko)
Salt & pepper to taste
Preheat the oven to 425°F. Remove the stems from the mushrooms and clean the caps.
In a food processor combine the cream cheese, basil, pine nuts and Parmesan cheese. Process until creamy (or use your immersion blender to achieve the same consistency). Add bread crumbs to the filling and mix well. Season with salt and pepper to taste.
Stuff each mushroom cap with approximately one heaping teaspoon of pesto filling. Bake for 20-25 minutes or until the tops start turning golden brown.
For an extra kick add some fresh garlic to the filling before processing.