2. Place the portabello on the pan with the smooth part down (not where the stem was).
3. Fill the cap, which is facing up, with either
sliced mozzarella or shredded cheese.
4. Cover and allow to cook until mushroom looks juicy and the cheese has melted (ab
5. Slice a bun, toast it.
6. Spread pesto on the bun.
7. Compile your sandwich with lettuce, kale or spinach and your cheesy mushroom.
For something extra:
grill coined slices of zucchini in same pan (yay! Less dishes). Place on bun, along with the sundried tomatoes.