In a bowl, mix together the hoisin sauce, soy sauce, rice vinegar, and sesame oil. Ensure everything is fully combined to create a flavorful marinade.

Add the thinly sliced beef and peeled shrimp into the marinade, making sure each piece is well-coated. Cover and let it marinate in the refrigerator for about 20 minutes.

While it’s marinating, heat the vegetable oil in a large skillet over medium-high heat. Add the minced garlic and sauté for about a minute until fragrant.

Once the garlic is aromatic, introduce the marinated beef and shrimp to the skillet. Cook for 5 to 7 minutes, stirring occasionally, until the beef is browned and the shrimp turns opaque and pink.

Now, toss in the sliced red bell pepper and broccoli florets into the pan. Stir-fry for about 3 to 4 minutes until they become slightly tender but still crisp.

Pour any remaining marinade over the skillet and mix well. Cook for an additional 2 minutes, ensuring everything is heated through.

Plate this colorful dish immediately, and serve it hot alongside steamed rice or noodles.