In a large mixing bowl, combine the ground beef with grated carrots, minced onion, chopped mushrooms, and grated garlic. Add the oyster sauce, sesame oil, brown sugar, salt, black pepper, cornstarch, and egg. Mix thoroughly with a spoon or clean hands until the ingredients are well combined and the texture is uniform. Set the mixture aside to rest for a few minutes, allowing the flavors to meld together.

Place a dumpling wrapper flat on your palm. Spoon about 2 teaspoons to 1 tablespoon of the beef mixture into the center of the wrapper. Dip your fingertip in water and moisten the edges of the wrapper to help seal it. Cup the wrapper between your thumb and fingers, pressing gently around the filling while keeping the top open. Adjust the folds to create a neat, upright shape. Repeat this process for all remaining wrappers.

Top each siomai with a small pinch of grated carrots for a pop of color and texture. Prepare your steamer by adding a small amount of water to the pot and bringing it to a gentle simmer over medium heat. Lightly brush the steamer tray or bamboo steamer with oil to prevent sticking.

Arrange the siomai in the steamer, ensuring they are spaced apart to allow steam to circulate evenly. Cover and steam over low heat for about 15 minutes or until the beef filling is fully cooked and firm to the touch. Avoid opening the steamer frequently to maintain steady heat.

Once cooked, carefully remove the siomai from the steamer and transfer to a serving plate. Serve warm with chili garlic oil or a dipping sauce made from soy sauce and calamansi for a classic, savory finish.

These tender, flavorful beef siomai are perfect as a snack, appetizer, or part of a hearty Filipino-style meal.