In this post, I would like to talk a little bit about the sauce that accompanies the filet mignon rather than the main protein itself. Briefly, the filet is prepared by grinding a good amount of fresh black pepper onto both the surfaces of the meat as well as sprinkling it with some salt. On a well-oiled hot pan, sear both sides of the meat well until they turn lightly brown (you don't want to burn the filet). Now, remove the meat and set it aside. You can fire it again in the oven when your sauce is finished.
For the tomato puree buerre blanc, which is a butter sauce, you will need 4 fresh tomatoes, a stick of butter, 1/2 cup of beef stock (or chicken stock), white wine and a of tablespoon of cream. First, cut up and then puree the tomatoes in a blender. To get a smooth and velvety texture, strain the pureed tomatoes, leaving behind the pulp and seeds. Now, using the same pan that was used to sear your filet mignon, pour away the oil, leaving behind the bits and pieces of the meat that are stuck to the pan. Turn on the heat and deglaze the pan with some white wine, scraping the bitty pieces of meat off the pan in the process. Add the strained tomato puree together with the stock. Start cooking the puree and stock mixture by first bringing it to a boil and then simmer for 30 minutes. Next, add the cream a little at a time and stir, making sure that it doesn't turn the sauce into a cream sauce. Again, let the sauce simmer for 10-15 minutes. Taste and season with salt and pepper. The final step is the butter. Cut the stick of butter into small chunks and add them into the sauce one at a time. Make sure that the sauce does not come to a boil as it will break the butter down into its milk solids, clarified butter and whey components. The purpose of the butter is to add depth and flavor to the sauce and also as a thickening agent. Again, taste and season the final sauce.
To put it all together, re-heat the filet mignon that was set aside earlier. The sauce can either be served over the meat or as a base on the plate.