Place bacon in a skillet over medium heat. Once fat starts to run from the bacon, add in 1 tbsp. of brown sugar to the pan and spread evenly. Alternatively, you can use turkey bacon with a bit of olive or sunflower oil and brown sugar.
Cook bacon until crisp. Allow to cool completely, and then chop the slices as small as possible. Set aside.
Heat a small saucepan over medium heat. Add the butter, chopped bacon (with a small amount of fat from cooking for flavor, if you prefer), thyme, basil, cayenne, and lemon juice, stirring often. Once butter is melted, add in garlic and 1 tbsp. of brown sugar. Allow the mixture to come to a gentle boil for about 30 seconds, and then simmer on low for about 5 minutes, or until garlic is fragrant. Continue to stir frequently to avoid burning.
Remove the pan from heat and allow to cool for about ten minutes. Then, place your filets in a sealable plastic freezer bag and cover them with the marinade. Remove as much air as possible as you seal the bag. Place in the refrigerator for about one hour (it may solidify some because of the butter).
If your marinade solidified, allow it to come to room temperature for about 15-20 minutes before you cook the filets. Preheat your oven to 425 degrees. In a cast iron pan over medium-high heat, sear each filet for about 3 to 5 minutes on each side until browned. Then, place in the oven for another 5 to 7 minutes, depending on how rare or done you like your steak. Add some leftover marinade to the top of each filet for some extra, juicy flavor.