Preheat the broiler.
Sprinkle the steak with the oregano, salt and pepper and place on a baking sheet. Broil the steak until well done, about 6 minutes per side. Remove from the oven and let cool before slicing. Slice or shred the steak into thin pieces and set aside.
In a large pot, combine the chicken stock, potatoes, jalapenos, onions and tomatoes, and bring to a boil over medium-high heat. Reduce the heat and add the shredded steak. Simmer the mixture for 2 hours until thickened.
Serve the Manchaca with warm flour tortillas to wrap.
This recipe was created by a contestant during a cooking competition. The Food Network Kitchens have not tested it for home use, therefore, we cannot make any representation as to the results.