Tri Tip and Caramelized Onion Sandwiches With Mustard Aioli

Tri-tip sandwich with caramelized onions
Sabrina S. Baksh/Regarding BBQ, Inc.
Prep: 20 mins
Cook: 33 mins
Total: 53 mins
Servings: 5 servings
Nutrition Facts (per serving)
925 Calories
61g Fat
39g Carbs
53g Protein
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Nutrition Facts
Servings: 5
Amount per serving
Calories 925
% Daily Value*
Total Fat 61g 78%
Saturated Fat 12g 58%
Cholesterol 153mg 51%
Sodium 2153mg 94%
Total Carbohydrate 39g 14%
Dietary Fiber 2g 9%
Total Sugars 7g
Protein 53g
Vitamin C 3mg 17%
Calcium 464mg 36%
Iron 5mg 29%
Potassium 742mg 16%
*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.
(Nutrition information is calculated using an ingredient database and should be considered an estimate.)

These tri-tip sandwiches are perfect for any kind of game night, cookout, or family dinner. The caramelized onions are a great accompaniment to the steak; however, the mustard aioli really ties it together. This will quickly become one of your favorite sandwiches.


  • 4 to 5 tri-tip steaks (about 1.5 pounds/700 g)

  • 1/4 cup (60 milliliters) olive oil

For Marinade:

  • 2 teaspoons (10 milliliters) apple cider vinegar

  • 2 teaspoons (10 milliliters) Worcestershire sauce

  • 1 1/2 to 2 teaspoons (7.5 to 10 milliliters) sea salt

  • 1 1/2 teaspoons (7.5 milliliters) onion powder

  • 1/2 teaspoon (2.5 milliliters) chili powder

  • 1/2 teaspoon (2.5 milliliters) coarse ground black pepper

For Onions:

  • 2 medium onions, sliced into 1/2-inch rounds

  • 3/4 cup (180 milliliters) beef stock, or chicken stock

  • 2 tablespoons (30 milliliters) olive oil

  • 2 teaspoons (10 milliliters) red wine

  • 1 teaspoon (5 milliliters) Worcestershire sauce

  • 1 teaspoon (5 milliliters) sea salt

  • Black pepper, to taste

For Mustard Aioli:

  • 1/2 cup (120 milliliters) mayonnaise

  • 1 tablespoon (15 milliliters) stone-ground or Dijon mustard

  • 1/2 teaspoon (2.5 milliliters) chili powder

  • 6 hamburger buns

  • 6 slices Swiss cheese

Steps to Make It

  1. Place steaks in a resealable plastic bag. Combine marinade ingredients, and pour over steaks. Make sure to work marinade well into the meat. Seal bag, and place into the refrigerator for 2 hours. 

  2. Preheat grill for medium-high heat. While the grill is heating up, slice onion, and heat olive oil in large skillet on the stove. Add onion, salt, and black pepper. Allow the onion to cook on high for 2 minutes, reduce heat to medium-low, and cook for 5 minutes, turning often. Add wine and Worcestershire sauce, let cook for 2 to 3 minutes. Add stock, reduce heat to low, and cook for 15 minutes.

  3. Place steaks on the grill, and cook for 10 minutes turning often. Steaks should cook quickly since they are relatively small and thin. If they are thicker, leave on for an additional 2-3 minutes. Remove from heat, and place onto the cutting board. Allow meat to rest for a few minutes before slicing.

  4. Prepare aioli by combining mayonnaise, mustard, and chili powder. If making ahead of time, place into an airtight container, and store in the fridge for up to 2 days after preparation.

  5. To assemble, place Swiss on the lower bun, add 6 to 8 slices of meat, 1/4 cup/60 mL of caramelized onion, and spread a generous amount of aioli on remaining inside half of the bun before topping sandwich.