Preheat oven to 325 degrees F (160 degrees C).
Cut the Cremini Mushroom (4 ounce) into 1/4-inch slices. Mince Garlic (2 clove). Remove the leaves from the stem from half of the Fresh Thyme (1/2 bunch).
Peel Russet Potato (2) and cut into 1/4-inch cubes and place in a bowl. Toss with Olive Oil (2 teaspoon).
Place potatoes on a sheet pan lined with foil and bake for 15 minutes.
Remove from the oven and raise temperature to 425 degrees F (220 degrees C). While oven is heating, place 2 pats of Butter (to taste) on the potatoes and gently stir until butter is melted and potatoes are well coated.
Once the oven reaches 425 degrees F (220 degrees C), put the potatoes back in the oven until edges are golden, about 10 minutes; remove from oven and season with Salt Salt (1/4 teaspoon). Toss and keep warm until plating.
Combine Dijon Mustard (1 tablespoon), Tamari Soy Sauce (1 tablespoon) and Granulated Sugar (1 teaspoon).
Add 85/15 Lean Ground Beef (1 pound) to bowl. Season with Salt (1 teaspoon) and Ground Black Pepper (1 teaspoon); mix well. Form the mixture into 2 equal sized patties.
Heat a medium sauté pan over medium high heat. Add Olive Oil (1 teaspoon) to the sauté pan. Add mushrooms and cook until soft, about 5 minutes.
Add Fresh Thyme (1/2 bunch) and garlic and cook for 2 minutes. Season with Salt (1/4 teaspoon) and Ground Black Pepper (1/4 teaspoon) and stir. Transfer to a plate.
Add the patties to the hot pan. Cook for 2 minutes. Turn over and spoon 1/2 of the mustard glaze over the patties and cook for 2 more minutes. Reserve remaining glaze.
Transfer to one side of a sheet pan, add one slice of Swiss Cheese (2 slice) to each burger and finish in the oven for 8 to 10 minutes. Separate the buns and place the Potato Bun (2) face up on the other side of the pan for the final minute of cooking.
Spread the remaining mustard glaze on the bottom halves of the rolls, and place on two plates. Add the burgers and top with mushrooms. Place the top bun on the burger. Serve with crispy potatoes.