In a large bowl, combine the meat, salt, pepper, paprika and flour. Make sure the meat is well coated. Reserve.
Heat one tablespoon olive oil in a large skillet, over medium heat, and then add the butter. Once butter is melted, add the grated onion and cook until it develops some color. Remove from heat and reserve.
In that same skillet, heat the remaining olive oil. When shimmering, add the beef and brown on all sides. Remove and reserve. Add the mushrooms and cook until they release liquid and are starting to brown, about 8 minutes.
Return browned beef and onion back to the skillet. Add the Dijon mustard, ketchup and Worcestershire sauce.
If flambeing, pour the cognac in a ladle and add it to the pan. Tilt the skillet so the fumes touch the flame. Cook until the flames are extinguished and all the alcohol is gone.
Stir in the blended peeled tomatoes and cook until thickened slightly, about 5 minutes.
Add the heavy cream. Cook for another 3-5 minutes or until sauce has thickened to your preferences.