In a mixing bowl, add the diced onions and minced garlic.
Sprinkle in the dried thyme, oregano, garlic powder, cayenne pepper, and red pepper flakes.
Pour in the balsamic vinegar, followed by the olive oil.
Use a whisk to mix the ingredients together. Continue whisking until the oil and vinegar are fully emulsified, and the seasonings are evenly distributed.
Let the marinade sit for 5–10 minutes, allowing the flavors to blend.
Place the wagyu tri-tip in a resealable bag or a shallow dish.
Pour the marinade over the meat, ensuring all sides are coated.
Seal the bag or cover the dish and refrigerate for at least 24 hours or up to 3 days for deeper flavor.
Remove the tri-tip from the marinade, and season it sea salt flakes and black pepper. Let it sit for 10 minutes.
Smoke and sear the Wagyu tri-tip to cook to your desired doneness.
Sauce
Transfer the leftover marinade to a saucepan and bring it to a gentle simmer over medium heat.
Let it cook, stirring occasionally, until it reaches at least 165°F to ensure it’s safe for consumption. For a thicker, more concentrated sauce, continue simmering until it reaches 180–200°F.
Once thickened, use an immersion blender to blend it into a smooth sauce.
Drizzle over the smoked and seared tri-tip before serving.
Notes
Baste the tri-tip with the juices released during cooking, slice against the grain for maximum flavor, and then drizzle with the sauce.