Hi Franky - first, may I suggest you do a search of this site on potatoes and mushrooms. There are many recipes already posted for soups and you might find just what you are looking for that way.

I wanted to give you a recipe for a side dish that uses both mushrooms and potatoes. I love blue cheese, so the original recipe suits me well. If you don't, consider using parmesan as a substitution.

Potato and Mushroom Bake
serves 4-5 as a side dish

1-1/2 pound potatoes
1 TBL butter or olive oil
8 oz. mushrooms, sliced
2 oz. blue cheese (or use parmesan)
2/3 cup cream (or evaporated skim milk)
1 egg
salt and pepper
4 oz. mozzarella cheese, grated or thinly sliced (or use swiss or provolone)

Spray a casserole or gratin dish with cooking spray and heat oven to 350F degrees.

Peel and slice potatoes into bite size pieces. Cook in simmering salted water until just cooked through. Do not overcook. Drain well.

While the potatoes are cooking, saute the
mushrooms on medium heat in a large frying pan
until softened and beginning to color on the edges. Add garlic and saute for another minute. Remove from heat.

In separate bowl, mash blue cheese slightly and stir in cream or milk and beaten egg. Season with salt and plenty of pepper.

Combine drained potatoes and sauteed mushrooms
in casserole or gratin dish and pour milk/cheese/ egg mixture over top. Lightly toss to coat. Top with grated mozzarella.

Bake for about 25 minutes until very hot and cheese topping is bubbling.