Chill a small baking sheet (1/4 sheet pan) in the fridge.
Combine 1/2 cup beef broth with the agar agar in a bowl and let sit.
In a medium saucepan over medium heat, heat the vegetable oil and add the shallots, mushrooms, remaining 1 1/2 cups beef broth, beer, salt and sugar. Bring the mixture to a rolling boil. Add the moistened agar agar and simmer 5 minutes. Remove from the heat. Pour onto the cold baking sheet and chill in the fridge until it forms a solid gel.
Slice the beef tenderloin into 1/4-inch-thick medallions and pound as thinly and evenly as possible.
Heat 1 tablespoon olive oil in a large skillet over high heat and sear the beef slices on one side. Sprinkle with truffle salt and black pepper. Cook in batches if needed, adding more oil if needed. Transfer the beef slices to a large plate or baking sheet and place in the freezer until ready to serve.
Cook the pasta. Drain and rub with olive oil.
In a bowl, mix the sour cream, beet juice and vodka. Chill until ready to serve.
Slice the chilled beef into perfect squares, 1-inch-by-1-inch. Do the same with the now solid mushroom gel.
Plate the pasta flat, 2 to 3 strips per plate should suffice. On top of the pasta, arrange a 3-by-3 grid of mushroom gel and beef squares. Garnish with beet sour cream and mushroom caps.
This recipe was created by a contestant during a cooking competition. The Food Network Kitchens have not tested it for home use, therefore, we cannot make any representation as to the results.