This is a very easy recipe with excellent results. The miso rub lends an Asian flair to this roast. You can also add garlic, ginger, and a bit of sesame or chili oil if you like. I like to serve this with oven-roasted bok choy, which I make while the beef is resting. Simply turn the oven up to 400ºF and toss halved bok choy in oil with salt and pepper, arranging them cut side down on a rimmed baking sheet. Cook for 8 minutes or so, until tender crisp, pouring pan juices over them as well during serving.
Combine miso paste, coconut aminos, and monk fruit in a bowl and place the tri tip into a greased baking pan. Rub all over with the miso mix, coating the roast evenly.
Bake for 1 1/2 to 2 hours, flipping the roast over halfway through baking time, until the meat measures 130ºF at the thickest point for medium rare, or until desired doneness.
Remove from oven and cover with foil and rest for 20 minutes. Slice against the grain and transfer to a serving platter. Serve any pan drippings over the slices.