Prepare the ingredients: slice the garlic and ginger, and set aside. Make sure the beef strips are at room temperature and the mixed vegetables are ready.

Heat a large pan or wok over medium-high heat and add 1 tablespoon of olive oil.

Add the beef strips to the pan in a single layer. Let them sear for about 2-3 minutes without stirring, to achieve a nice browning.

Stir the beef strips and cook for an additional 2-3 minutes, or until they are cooked through. Season with salt and pepper to taste, then remove the beef from the pan and set aside.

In the same pan, add another teaspoon of olive oil (optional) and the minced garlic and ginger. Sauté for about 30 seconds until fragrant.

Add the mixed vegetables to the pan and stir-fry for about 3-5 minutes, until they are tender but still crisp.

Return the cooked beef to the pan with the vegetables. Pour the soy sauce and sesame oil over the mixture, stirring well to combine all the flavors. Cook for an additional 1-2 minutes.

Serve the beef stir-fry over the cooked brown rice. Enjoy your meal!