In a mixing bowl, combine the soy sauce, coconut milk, vegetable oil, minced garlic, minced ginger, brown sugar, ground black pepper, ground coriander, and ground cumin.
Mix well until the sugar is dissolved and the marinade is well combined.
Place the beef steaks in a shallow dish or resealable plastic bag.
Pour the marinade over the steaks, ensuring they are well coated.
Cover the dish or seal the bag and refrigerate for at least 2 hours, preferably overnight.
Preheat your grill or a large skillet over medium-high heat.
Remove the steaks from the marinade, allowing any excess to drip off.
Grill or sear the steaks for about 4-5 minutes per side, or until they reach your desired level of doneness.
Remove the steaks from the grill or skillet and let them rest for about 5 minutes to allow the juices to redistribute.
Slice the steaks against the grain and transfer to a serving platter.
Garnish with chopped fresh cilantro or parsley.
Enjoy your meal!