Peel and chop the potatoes into ½" cubes and place them in a large pot of boiling water. Boil for 12-15 minutes, until they are easily pierced with a fork.
While the potatoes are boiling, make the mushroom cream sauce. In a small saucepan, bring the vegetable broth to a low simmer. In a separate saucepan, melt 1 tablespoon of vegan butter over medium heat. Add the flour, one tablespoon at a time, and mix with a wooden spoon until fully incorporated making a roux. Cook for 30-60 seconds stirring constantly.
Add the vegetable broth, one-half cup at a time, whisking vigorously to avoid the flour from clumping. Whisk until all the vegetable broth is incorporated. Bring to a boil and then reduce heat to a simmer. Simmer for 30 minutes. Once thick, remove from heat, whisk in vegan creamer or non-dairy milk, and set aside while you prepare your gnocchi.
Once your potatoes are soft, strain them through a colander shaking off any excess water. Place them in a metal bowl. Using your Dome Dough Maker, mash the potatoes until they are completely and thoroughly mashed.
Add the flour and salt to the mashed potatoes and gently knead it together with the Dome Dough Maker until it forms a soft dough. The dough should be soft but not sticky.
On a floured surface, divide the dough into four pieces. Roll each one out evenly into a long rope that is ½" - ¾" in diameter. Using a sharp knife, cut the rope into 1" pieces. Make indentations with a fork on the front and back of each dumpling (this is optional).
In small batches, place the gnocchi in boiling water and boil for about 60 seconds. The gnocchi is done when the pieces float to the top. Scoop them out with a slotted spoon and set them aside. Repeat until all the gnocchi has been cooked.
To finish the sauce, heat the remaining tablespoon of butter over medium heat. Add the shiitake mushrooms and sauté for 2-3 minutes until golden brown. Strain the thickened velouté sauce through a fine mesh strainer and add to the mushrooms. Stir in the gnocchi and serve immediately with fresh parsley, freshly ground pepper, and vegan parmesan (optional).