Pat meat dry and thinly slice the meat into strips against the grain of the meat.
Add seeds and peppercorns to a small skillet over medium heat and toast a minute until fragrant. Place in spice mill and grind. You can use ground spices instead and skip the toasting step. Combine with chili powder, garam masala, and turmeric.
Peel and slice red onion. Seed and thinly slice bell pepper. Optional: Thinly slice or chop the fresh Serrano or jalapeno peppers. Seed if you prefer milder food or leave seeds in for extra spicy. Grate or mince ginger and garlic.
Heat a large cast-iron skillet over medium-high to high heat. Add a tablespoon of oil and cook beef in single layer to brown and crisp, 2 to 3 minutes on each side. Season with salt and remove to platter. Add another tablespoon of oil, and add onions and peppers, toss, and cook for 3 minutes. Add ginger and garlic, and toss a minute more. Add beef back to pan, sprinkle in spice blend, toss to combine with peppers, and add apple cider vinegar. Garnish beef with cilantro. Serve beef with rice.
