Step 1
Preheat oven to 375°F (190°C).
Step 2
Place beef tenderloin on countertop to come to room temperature.
Step 3
Combine onions, green onions, pearl onions, garlic, thyme, butter and canola with a small amount of salt and black pepper. Put in a pan (ideally cast iron) and place in the preheated oven.
Step 4
Roast onions until lightly golden and very tender, approximately 30 minutes.
Step 5
Leaving as much butter and oil in the pan as possible, transfer the onion mixture to a bowl and use a fork to lightly mash the garlic, almost like a paste. Mix garlic paste throughout onion mixture.
Step 6
Using the same pan you cooked the onions in, with butter and oil reserved, place the pan on the stove top over medium-high heat.
Step 7
Season tenderloin with salt and pepper and then place it in the hot pan. Sear for 1-2 minutes per side, depending on your preferred degree of doneness. (For a medallion with a 3cm thickness, a 2 minute sear per side will give you a nice medium centre.)
Step 8
Spoon onions over tenderloin, spoon vinegar over onions and cover with a piece of Albert’s Leap Le Bon Secret.
Step 9
Place pan back in oven for 1 minute until cheese is just melted.
Step 10
Remove from oven and let rest for 3-5 minutes before serving.
Enjoy!