How to Make It
In a large bowl, toss the beef tenderloin with the pepper, cumin and 1 tablespoon of the soy sauce. In a large skillet or wok, heat the oil until shimmering. Working in batches, add the beef strips and stir-fry over high heat until lightly browned, about 3 minutes per batch. Transfer the beef to a bowl with a slotted spoon.
Add the garlic to the skillet and cook over moderate heat, stirring, until golden, 30 seconds. Add the onions and stir-fry until softened, 5 minutes. Add the jalapeños and cook, stirring, for 1 minute. Add the vegetables to the beef in the bowl with a slotted spoon. Add the tomatoes to the skillet and cook, stirring, until slightly softened, 2 minutes.
Increase the heat to high and return the beef and vegetables to the skillet. Add the wine, stock and the remaining 3 tablespoons of soy sauce and stir-fry for 3 minutes. Add the cilantro and Oven-Fried Potatoes and toss gently. Transfer to a platter and serve.