Add the cubed potatoes to a medium pot and cover with 1 inch of water. Set over medium-high heat and bring to a boil. Cook until fork-tender, then drain and set aside.

In a large, deep skillet over medium heat, melt the butter. Add the shallot and cook, stirring often, for about 2 minutes, until softened.

Add the cooked potatoes to the skillet. Cook for 5 minutes, stirring occasionally, until lightly browned.

Stir in the cubed seitan roast, parsley, salt, pepper, and thyme.

Continue cooking for 10 minutes, stirring often, until the hash is lightly crisped. Serve warm.