If you make hemp seed bacon bits, bake them while making the sauce and getting the potatoes ready. In this case, you won't need to preheat the oven (step 4).
Start the sauce. Preheat a medium to a large saucepan over medium heat. Add the shallots and stir to soften them for about a minute. Then stir in the plant milk, nutritional yeast, garlic powder, thyme, black pepper, and paprika. Stir and adjust the heat.
Mix broth and cornstarch. Add the vegetable broth to a small dish or jar and add 1 tablespoon of cornstarch. Mix until there are no lumps.
Finish the sauce. Add the vegetable broth mixture to the sauce and stir until the sauce is smooth and starts to bubble. Turn the stove on low and let the sauce continue thickening while you prepare the potatoes.
Preheat the oven to 425 degrees (220 C). Grab a baking dish (casserole dish) about 9 x 13 inches with enough depth to layer the potatoes and sauce.
Peel and thinly slice the potatoes. Layer half of the potatoes on the bottom of the baking dish and pour on half of the sauce. Sprinkle half of the bacon bits over the sauce. Repeat with the rest of the ingredients.
Bake the potatoes. Cover the dish with aluminum foil and place the potatoes in the center of the oven. Bake for 30 - 35 minutes until the potatoes are tender. Remove the foil and bake another 10 minutes until the top is brown and crisp.
Set the dish. Remove the potatoes from the oven and replace the foil. Let the potatoes sit for 5 minutes. The sauce will thicken as it cools.
Notes
To reheat, place the potatoes in an oven-proof baking dish covered with foil. Bake until they are heated, then remove the foil and crisp the top for another 5 minutes. Place leftovers in an airtight container and store them in the refrigerator for 4 days.
The bacon bits and sauce can be made a day ahead. Peel and slice the potatoes right before cooking to prevent oxidation.