Wash your mushrooms and carefully take off the stems if there is one. Rub mushrooms lightly in olive oil and set aside.
In a mixing bowl, combine cream cheese, bread crumbs, Parmesan cheese, basil, grated (or pressed) garlic and salt. Mix very well until all combined.
Place mushroom cups onto a baking sheet. Carefully and evenly fill the cups with cheese mixture pressing down lightly with your fingers to spread it out.
Grate some fresh Parmesan over the mushrooms.
Bake fore 15-18 minutes.
Build burger by adding some arugula on the bottom bun, stuffed mushroom on top and pesto on top of mushroom.