Slice your sirloin into ¼-inch strips against the grain. Use a meat mallet to gently flatten the pieces for an even texture.

Place the strips in a zip-top bag with the cornstarch and coat evenly. Let it rest for 15 minutes to allow the coating to set.

Heat canola oil in a skillet over medium-high heat. Sear the beef in batches, cooking for about 30 seconds on each side.

Once done, transfer the beef to a plate and season lightly with salt.

In the same skillet, add minced garlic and grated ginger, sautéing for 10–15 seconds until fragrant.

If desired, add chili oil or red pepper flakes for an extra kick.

Pour in the tamari, water, and brown sugar, stirring to combine. Bring the mixture to a boil for one minute to develop flavor.

Return the seared beef to the pan, stirring to coat it in the sauce. Let it simmer for another 30 seconds to thicken.

Turn off the heat and toss in the scallions. Serve hot over white rice, rice noodles, or in fresh lettuce wraps.