Cheesy Potato without lasagna bouillon vegetables

1/4 cup butter 1/2 stick, or half olive oil and half butter 1 pound mushrooms white or cremini, sliced 1 tablespoon garlic minced 4 cups leeks thinly sliced[...]

3 medium potatoes peeled and chopped 1 large onion minced 1 1/2 cups chicken broth 1 x american cheese to taste * 1 x salt and black pepper to taste * 1 x[...]