For the Steak:

• 1 1/2 pounds sirloin or flank steak (cut into bite-sized cubes)
• 2 tablespoons soy sauce
• 1 tablespoon sesame oil
• 1 tablespoon rice vinegar
• 2 cloves garlic (minced)
• 1 teaspoon ginger (grated)
• 2 tablespoons butter (divided)

For the Vegetables:

• 1 zucchini (sliced into half-moons)
• 1 cup mushrooms (sliced)
• 1 small onion (sliced)
• 1 cup broccoli florets

Additional:

• 2 cups cooked jasmine or white rice
• 1 tablespoon toasted sesame seeds (optional)
• Sliced green onions for garnish (optional)

For the Yum Yum Sauce:

• 1/2 cup mayonnaise
• 1 tablespoon ketchup
• 1 teaspoon rice vinegar
• 1/2 teaspoon garlic powder
• 1/2 teaspoon paprika
• 1–2 tablespoons water (to thin)
• Pinch of sugar