Peel and chop potatoes. Add to pot of boiling water with a pinch of salt and boil until tender.
While potatoes are boiling, add to first mixing bowl the carrots, sweet onions and celery then place bowl to the side.
Add to second mixing bowl the mushrooms, mashed SPAM, fishcake, eggs and green onions and completely mix ingredients together.
Grab first mixing bowl and slightly saute ingredients until beginning to become translucent and remove from heat. Once your mirepoix has cooled, you may add it to your second mixing bowl.
Potatoes should be done by this time if not done already and should also be removed from heat. Drain potatoes and begin mashing. After you have completed mashing all the potatoes, add to other ingredients.
Take 1/8 cup and tightly squeeze mixture and form to make patties.
After all patties have been made, place patties in a hot lightly oiled or PAMmed frying pan and give each side a light sear for coloring. Plate and serve.