For the Buns:

1. In a large pot of salted boiling water, cook noodles according to package directions. Drain and let cool, then toss with beaten egg. If desired, substitute 2 egg whites instead of 1 large egg. Season with salt and garlic powder.
2. In a large skillet over medium heat, heat oil. Press noodles into four wide mouth Mason jar lids and add to pan. Fry until golden, 3 minutes per side.

For the Burgers and Topping:

1. In a large bowl, mix ground beef with Dijon and paprika and season with salt and pepper. Form mixture into two patties. Add burgers to skillet and cook 5 minutes per side.
2. Meanwhile, in a medium skillet, heat butter over medium heat. Add shallot and sauté until translucent. Add mushrooms and cook until slightly softened. Add garlic and cook 1 minute more. Flour. Pour in beef broth and bring to a simmer, then remove from heat and stir in sour cream.