To a large bowl, combine ground beef with the egg, breadcrumbs, salt, pepper and grated shallot. Mix with your hands until just combined. Divide beef mixture into 4 equal portions, and shape each portion into a ball. Set aside.
Dice the shallots, mince the garlic cloves and chop the chives.
Heat oil and butter in a large thick-bottomed skillet or an iron skillet over medium high. Add beef balls, press down on each one by using a spatula or a burger press until ¾ inch or 2 cm thick. Sear 5 minutes per side. Remove from skillet onto a clean plate.
Reduce heat to medium, add garlic and shallot. Cook for 1 minute. Stir in mustard, salt, pepper and flour.
Deglaze with whiskey and simmer for 3 minutes while stirring and scraping up the brown bits on the bottom of your skillet with a wooden spoon.
Pour in beef broth and bring to a boil. Pour in cream and stir until combined. Return the hamburger steaks to the skillet, spoon sauce on top and simmer for 5 minutes.
Finish off with chopped chives and freshly grated black pepper. Enjoy!
