Pat beef dry, season with salt and pepper. Heat 1 tbsp oil in a large skillet over medium-high. Sear beef in a single layer, 2 minutes per side, until browned. Transfer to a plate.

Reduce heat to medium, add remaining 1 tbsp oil. Sauté mushrooms and onion 6 to 8 minutes until browned and tender. Stir in garlic 30 seconds.

Sprinkle flour over vegetables, stir, and cook 1 minute. Whisk in beef broth, simmer 3 to 4 minutes until slightly thickened. Stir in coconut cream, mustard, and vinegar. Return beef and any juices to the pan, reduce heat to low, and simmer 5 minutes. Adjust salt and pepper.

Ladle over noodles, garnish with parsley, and serve hot.