Preheat oven to 425°.
Bring a stockpot of water to a boil. Drop in the chopped potatoes and boil for about 10 minutes. When potatoes are tender, drain and then pass them through a vegetable mill into a large bowl or mash them in the bowl with a potato masher. Add salt and olive oil and mix to incorporate. Slowly stir in spelt flour until you get a dough that is supple without being too sticky.
Working on a floured surface, roll the dough into inch-thick ropes. Starting from the end of a rope, cut off a small piece and roll it with the edge of a fork to create grooves on 1 side and a hole in the other. Set aside on a floured plate. Continue cutting and rolling pieces until you have shaped all the dough.
As you are shaping the gnocchi, bring a large pot of salted water to a boil. Add the gnocchi in small batches and remove them from the boiling water with
a slotted spoon when they rise to the top. Place them in a baking dish and keep warm in a 250° oven, if desired.
Serve the gnocchi with the Spinach-Mushroom Sauce.