Preheat the oven to 400 degrees F (200 degrees C). Line a baking sheet with a silicone liner or parchment paper.

Combine butter, garlic, lemon zest, Dijon mustard, salt, red pepper flakes, smoked paprika, black pepper, cayenne pepper, thyme, chives, and parsley in a bowl; mash and mix until evenly combined. Add lemon juice and mix until thoroughly incorporated.

Generously apply the butter to both sides of bread slices and place on the prepared baking sheet.

Bake in the preheated oven for 10 minutes, then turn the bread over, and bake until toast is as browned and crisp around the edge as you like, 7 to 10 minutes. Set aside until needed.

Transfer remaining butter onto a piece of plastic wrap, and shape into a 2-inch diameter cylinder. Refrigerated until needed, then slice into medallions for serving.

Turn the steak on its side, and slice down the middle, cutting the filet into 2 equal sized 4-ounce portions. Season both sides with salt.

Place a skillet over high heat, and add avocado oil. Once the oil is shimmering, sear steaks for about 2 minutes on each side, or until they are cooked to your desired doneness. Turn off the heat, and transfer the steaks on your plate to rest for 3 to 4 minutes, while you deglaze the pan.

To deglaze pan, add beef broth into the still-hot pan, and scrape the bottom with a spoon or spatula to release any caramelized bits. There should be enough heat in the pan to reduce the liquid down to about 2 tablespoons, but if not, turn the heat to medium-high until reduced.

Place steak on toast, and drizzle over the pan drippings. Top with a slice of cowboy butter, and enjoy.