To make crispy onions, add sliced onions on paper towel as they will release some liquid. Heat either olive oil or vegetable oil in a sauce pan to about 2-3 inches in depth. Mix flour and paprika in a bowl and coat sliced onions. Once hot, add sliced onions and allow to fry for about 4-5 minutes, long enough so they are crispy. Place on paper towel and set aside.
Remove beef medallion from the refrigerator about 15-20 minutes before cooking. Season with salt and pepper and set aside.
Heat a cast iron pan, over medium-high heat, add olive oil and once oil is hot, carefully add the beef medallions into skillet and pan-sear the sides until golden and crispy, moving the medallion as you sear it. Then lay flat and pan sear each side of the medallion for 3 minutes on each side for medium-rare steak. Transfer to a plate and cover.
On medium heat, using a fry pan or skillet, melt the remaining 2 tablespoons of butter. Stir the butter and swirl the pan occasionally for about 3 minutes, until the foam settles. The butter will change colour to golden brown. Then add garlic, thyme and rosemary and simmer for about a minute or two, long enough to release the aromas of the garlic and herbs.
Return the beef to the skillet and using a spoon, coat the brown butter over the medallions several times while they are warming. This will add more flavour and juiciness to the steaks. Do this several times until the steaks are hot.
Serve with whipped potatoes, buttery green beans. Top each medallion with Boursin while it's hot to allow the cheese to melt slightly. Then add the crispy onions. Garnish with fresh rosemary and microgreens. Enjoy!