To make the bearnaise, place the egg yolks and the coconut vinegar into a blender and pulse to blend. With the blender running very very slowly drizzle the butter until thickened. Stir in the tarragon and season with salt.
To make the steaks, season filets on all sides liberally with salt.
Heat a cast iron with bacon fat over high heat. Once hot, place filets in skillet and sear for 4 minutes on each side. Lower heat to medium and use a meat thermometer and cook to 130 degrees for medium rare or 140 for medium. Remove from skillet and allow to rest for 10 minutes.
While filets are cooking, make the asparagus. Place water in a large skillet that is 1 inch deep. Add 2 tablespoons salt. Bring salted water to a boil. Add asparagus in one layer. Cook until tender, about 5 minutes for medium and 7 minutes for jumbo. Drain, and transfer to a serving platter. Sprinkle with salt, and top with a pat of butter.
To make the crab, melt 1 tablespoon butter in the skillet. Toss crabmeat in butter just long enough to heat it, being careful to not break it apart.
To assemble, place filets on serving plates. Spoon sauce over steak, top with crabmeat, and serve with asparagus.
Best served fresh.