1 Beef Bou cube, dissolved in one cup of water (or 1 cup beef broth)
1 big sprig of Rosemary
1/4 cup sherry
Olive oil
1 cup Panko bread crumbs
1/2 cup parmesan, grated
Parsley to taste
Preheat a large, heavy skillet on medium-high heat.
Pat tenderloin dry and season liberally with salt and pepper.
Drizzle enough grapeseed oil (or your preferred high heat neutral cooking oil) in the heated pan. Place the seasoned tenderloin in the pan and sear on all sides.
Turn down the flame on your pan and set tenderloin on a parchment-lined sheet tray with a rack.
Place into a 400ºF oven and roast for 15-20 minutes or until the internal temperature is 135º.
In the meantime, put sliced onions in the skillet, scraping the bottom of the pan to release any fond. Once your onions have become soft and lightly caramelized, turn off the flame completely and add in sherry.
Turn back on the heat and scrape the bottom of the pan with a wooden spoon to deglaze. Simmer sherry until it's reduced by about 1/2. Add in beef broth and simmer.
Adjust seasoning with salt and pepper.
Remove the roast from the oven and allow to rest for at least 20 minutes before slicing.
To serve, line a platter with the french onion sauce, slice tenderloin into 1-inch slices and top with Parmesan parsley bread crumbs.
To make the"crouton" topping:
In a medium skillet, heat up about 2 tablespoons of olive oil and add in panko bread crumbs and stir until golden brown. Set in a bowl to cool.
Once bread crumbs have cooled, add in finely grated parmesan cheese(a Microplane is great for this!) and minced parsley.