Combine all the GRAVY ingredients in a small bowl. Mix well and set aside.
Lightly salt and pepper the sliced beef.
Heat a wok or skillet over high heat. Add a tablespoon of oil, swirl it around the pan and allow it to heat up.
In a separate bowl, combine Maggi Seasoning and oyster sauce with a ¼ cup of water.
Turn the heat down to medium, add pho rice stick noodles and the sauce mixture and give it a good toss. The noodles will begin to soften as it cooks.
If the noodles are still too dry or begins to clump into a large ball, add a tablespoon of water to help loosen it. Repeat if necessary until the noodles are cooked through.
Place the noodles onto a serving plate and set aside.
Heat another tablespoon of oil over high heat then add the beef.
Allow it to brown on one side, then flip to brown the other side. Add minced garlic.
Add the greens and stir fry until the veggies are almost cooked through.
Give the Gravy mixture a good stir as the cornstarch would have settled by now. Pour it into the wok and toss with the beef and vegetables until the sauce thickens.
Pour the stir-fry over the bed of pho noodles. Serve with freshly cracked black pepper.